Collins opened the scoring with his fifth goal of the season, before Pearson - who started his career at Ewood Park before dropping into Non-League seven years ago - restored the lead just before the hour after Lewis Travis had hauled the tenth-places hosts level towards the end of the first half.
It required a backs-to-the-wall performance at times in the second half, which included Rovers having a Bradley Dack tap-in ruled out for offside.
But Graeme Jones' men dug in to bring a run of three league and cup defeats to an end with a second away win in the Championship this season, and third overall, to jump to 16th in the table.
Jones made three changes to the side that went down 3-0 at home to Hull City last weekend, as Pelly-Ruddock Mpanzu, Jacob Butterfield and Dan Potts came in for Andrew Shinnie, Kazenga LuaLua and Luke Bolton.
Callum McManaman and Luke Berry were recalled to the bench, with George Moncur and Shinnie dropping out of the 18-man squad altogether, the latter with a knee injury.
Blackburn had made all of the early running, with captain Sonny Bradley heading several dangerous-looking crosses away from his own six-yard box as former England winger Stewart Downing and Adam Armstrong tested the back four.
It was against the run of play when the Town grabbed the lead in the 17th minute, but it came courtesy of a brilliant first touch and cross from Izzy Brown on the right of the Rovers penalty area, picking out top scorer Collins to place his header past ex-Hatters loanee Christian Walton and into the top corner.
The goal brought up a milestone for the Republic of Ireland striker, with his half-century for the club coming in his 102nd game, and his 30th in 48 appearances since opening his account for last season with his goal against Charlton on September 29th last year.
Town started to get the ball down and play some lovely possession football, Butterfield pulling the strings with Mpanzu and Tunnicliffe either side of him and Collins and Cornick posing a threat from wide areas. Brown was through the middle, looking for any opportunity to create.
The hosts' first attempt on goal didn't come until the 35th minute, but Simon Sluga could breathe a sigh of relief as Bradley Johnson dragged his shot well wide.
Two minutes later it was a different story, however, as Downing fed Travis from the right flank and the Rovers midfielder took one touch before firing across Sluga and into the far corner from the edge of the box.
James Bree, back in his more natural right-back position after impressing on the left since his arrival on loan from Aston Villa, did well to head a deep cross behind under pressure from Sam Gallagher as half-time approached.
Cornick was the first to have a go in the second half, eight minutes after the break, as the Hatters broke at pace from their own box, Butterfield intercepting a low cross and feeding Tunnicliffe, who picked out Brown to slip Cornick in on the right side of the Rovers penalty area. Walton was equal to this one though, turning the three-goal forward's powerful drive around his near post.
The Town were back in front in the 57th minute, however, and how Pearson enjoyed his moment against the club who released him as a teenager.
Cornick was fouled on the right and Brown curled in a free-kick from deep. Pearson, whose journey has taken him to FC Halifax, Accrington and Barnsley before arriving back at the same level as his boyhood club, rose high above his marker Darragh Lenihan to direct his header into the bottom corner, before sprinting to the Town technical area to celebrate.
Rovers rallied immediately. Downing bent a 20-yard free-kick around the wall, but thankfully the wrong side of the post, after manager Tony Mowbray made a double substitution, bringing former Tottenham and Hamburg midfielder Lewis Holtby, the German international, on for Johnson, and vastly experienced striker Danny Graham for Gallagher.
Graham was soon calling Sluga into action with a smart save low to his right as a volley skidded through on the rain-soaked surface, then Holtby pulled a left-footed shot into the side-netting with a little over 20 minutes to go.
Blackburn were knocking at the door, but Armstrong couldn't keep his left-footed drive down when Derrick Williams had played him in over Pearson's head, then Potts did well to divert a deep cross from Downing behind under pressure from Graham.
McManaman, who had been introduced for the excellent Brown, produced a stinging shot that Walton had to beat away in the 74th minute, with Mpanzu unable to capitalise on the rebound, then Butterfield produced a vital challenge in his own area before Bradley Dack hit a shot high over Sluga's bar.
Soon after Bradley and Potts had put their bodies on the line to block a Dack drive, Rovers had a goal ruled out with 12 minutes to go as Williams climbed highest to meet a right-wing corner, but Dack was in an offside position as he turned the ball home from two yards out.
It took a while for referee Gavin Ward to make the decision, but after consultation with his assistant on the near side, the Town fans behind the goal breathed a huge sigh of relief and with Lloyd Jones thrown on in the closing stages to stiffen up the backline, their team managed the final few minutes brilliantly.
Now it's back to Kenilworth Road on Wednesday night for the live Sky clash against a Millwall team sitting one place below the Town in 17th, but on the same points total of ten.
TOWN: Sluga, Bree, Pearson, Bradley (c), Potts, Butterfield (Berry 83), Tunnicliffe, Mpanzu, Cornick (Jones 86), Brown (McManaman 71), Collins. Subs: Lee, Bolton, LuaLua, Jones, Shea.
Goals: Collins 17, Pearson 57
Yellows: Butterfield, Potts
ROVERS: Walton, Bennett (c) (Samuel 81), Lenihan, Williams, Cunnigham, Downing, Travis, Johnson (Holtby 61), Armstrong, Gallagher (Graham 61), Dack. Subs: Leutwiler (GK), Bell, Adarabioyo, Buckley.
Goals: Travis 37
Yellows: Travis
REFEREE: Gavin Ward
ATT: 15,319 (1,326 Hatters)
