Thomas Hearns was knocked out by Sugar Ray Leonard and Marvin Hagler but still became a 5 time division champ.
Hearns' KO wasn't really devastating... It was a fight that could have gone either way and he was simply exhausted. Still a knockout but I don't know if I'd call it devastating
zab judah courtesy of kostya,corrales by mayweather,duran from hearns,lewis from mccall,ruiz from tua,wlad klit from various
Judah and Corrales never recovered
Hearns vs. Hagler
This came to my mind, however Hearns broke his hand early on in the fight so that loss to me is somewhat tainted, as I believe Hearns was on course to knock Hagler out...
I should also mention the destruction of Pipino Cuevas in the second round to Hearns (or 1st I don't remember). He was able to come back and have success in the ring as well...
Mike Tyson to Douglas
Manny earlier on
Evander Holyfield to Riddick Bowe (I think the 2nd or 3rd fight. he was wearing gold trunks)
Tommy Morrison suffered some nasty KO's and would come back to win fights
Amir Khan was cold clocked by Prescott but has had success since and I think will have more success in the future
Larry Holmes has one KO in his career against Tyson yet went on to win 20 more fights and have 3 more shots at the title, and also defeated an undefeated Ray Mercer.
Miguel Cotto had an impressive performance against Pacquiao even after his destruction at the hands of Margarito and he also looked very good against the naturally larger Yuri Foreman (who I believe is more in Cotto's class, than an elite like Pac).
Ray Mancini was knocked out by Alexis Arguello in a 14 round battle yet went on to have much success in his career.
Alexis Arguello took some massive punishment, getting brutally outslugged by the faster, more aggressive Aaron Pryor in 2 battles yet came back and had some success over the next decade.
There are many fighters who have been KO'd who have come back and had success.....