The visitors were in total control at half-time after captain Charlie Adam, back from a two-game ban, had netted a contentious 25th-minute penalty and curled in a sublime free-kick four minutes later.
But Christopher Samba pulled a goal back for Blackburn four minutes into the second half and their incessant pressure finally paid off when Richard Kingson failed to get hands to a free-kick from opposite number Paul Robinson and Hoilett headed in.
The result keeps both sides a point above the relegation zone, but Blackpool will know this was a great chance to take a giant step towards safety.
There was no sign of what was to come in the opening stages as Blackburn dominated proceedings against an unusually timid Blackpool.
Jermaine Jones saw an acrobatic effort deflected over while Steven Nzonzi headed just wide from eight yards after Kingson had flapped at a corner.
Having offered next to nothing going forwards, Blackpool thought they had taken the lead in the 20th minute when Adam's free-kick was turned in by Luke Varney, but he was correctly, if belatedly, flagged offside.
The visitors then had a let-off when Hoilett's cross just failed to pick out an unmarked Mame Biram Diouf, but in the 25th minute Blackpool did take the lead from the penalty spot.
Jason Puncheon broke through from midfield before playing in Gary Taylor-Fletcher, who appeared to get his shot away before he was caught by Ryan Nelsen, back in the Rovers team after a one-match suspension.
Blackburn, who had lost out to a dubious penalty at Fulham last time out, were furious with referee Howard Webb but it was to no avail as Adam coolly rolled his shot into the bottom corner.
The massed ranks of Blackpool fans who had made the short trip across Lancashire were ecstatic, and they were celebrating again four minutes later when Adam doubled the lead.
There was no luck involved this time as, after he had been fouled 25 yards out by Jones, the midfielder picked himself up to curl a precise shot into the top corner.
In the closing moments of the half Varney had the ball in the net again after following up a shot from Puncheon that was parried by Paul Robinson, but this time the midfielder knew the offside flag was coming.
What Blackburn needed was good start to the second half, and they should have pulled a goal back in the opening seconds when the lively Hoilett worked his way into the area on the left and picked out Nzonzi, who fired into the side netting from 12 yards.
The home fans did not have to wait long, though, as a spell of pinball in the Blackpool box in the 49th minute ended with captain Samba sending a low shot into the bottom corner.
Kingson failed to hold a cross and, after Hoilett and Diouf had both seen shots blocked, Samba kept his head to beat the keeper from 20 yards.
A rare foray forward from Blackpool ended with Puncheon forcing a decent save from Robinson but the visitors' defending was becoming increasingly desperate and Martin Olsson slammed a shot against the post.
Teenage Blackburn defender Phil Jones, out since December with a knee injury, was thrown into the action for Emerton in the 59th minute.
Blackpool were enjoying more possession now but they were still walking a tightrope and Samba came agonisingly close to levelling matters in the 76th minute with a header that was cleared off the line by Stephen Crainey.
The centre-back then saw his follow-up attempt deflect wide off Rovers substitute Jason Roberts, who moments later hooked a shot against the outside of the post.
The hosts continued to pour forward, with Samba and Hoilett both sending efforts wide, and in the third minute of injury time they finally got the equaliser they craved.
Kingson could not get hands to a long free-kick from Robinson and Hoilett headed over keeper and defence to secure a priceless point for the hosts.