Yep....skyrocket.....by a level or 2. Honestly if I recall this is the biggest level jump he's managed so far in the series and he still can't become a legitimate adventurer after it. He also won't ACTUALLY level until he looks at his status which is something he eventually both seems to realize and also still almost never looks. For whatever reason his stats actually TRY to hide themselves from him and until he realizes he is higher level or improved his skills they tend to sit at the same level. Like his own powers are trying to hold him back as much as possible....probably for his own safety. I mean this man in the story literally dusted his own bones multiple times in this fight, burst blood vessels, tore up every muscle...... this guy basically LIVES off stuffing mushrooms down his throat until he learns a self regen ability from it and then he just pushes his body further because it can survive more.
It really didn't come through in this manga but he is functionally the de-terminator, if it doesn't outright kill him he doesn't give a fuck gets back up and continues killing himself to accomplish his goals.
Also on levels specifically
He later seems to realize that to pass level level 99 or 100 his classmates need to beat a lvl 99 boss and then SUDDENLY jump forward......based on how things in the novel go though I'm starting to think that the cut off point for him might be every 10 levels instead or something. Since lvl 99 bosses seem to be just about the only way he ACTUALLY improves level wise.