After blotching the opening, I was waiting to be squeezed to death.  After sacrificing the exchange, I had a way to develop my remaining queenside pieces and, together with some pawns I'd snatched (my only play in the early middlegame) took control of the game.

You were never in the grip of a boa constrictor at all. Your play was solid and though your pieces appear stuck behind your pawn chain, all you have to do is make some exchanges, crack open the position and you're just as active as him.

You didn't have to sacrifice the exchange either, though that is the quickest route for a rapid attack. Slow pawn maneuvering and actively taking up good outposts would eventually guarantee an overwhelming piece activeness advantage.

If you mean he blundered a bishop, then yeah, you took totally took control

Qa5 clogs you up more, it's handy to be aware of the idea a5 with Ba6

"Cracking it open" was easier said than done as my Bc8 had NO way to get out and the Nb8 could (after a5) perhaps do something useful after Na6-c7-e8.  The Ra8 has to work around both of them.  Not giving up the exchange would have given White no problems with essentially two plus extra pieces in play.

After missing 23. f4! and especially after dropping the bishop, White showed he still has to improve his tactics to get better.

LOLZ    (see picture)