Fish-sitting - noticed growths on JD's head. Help?

Like the title states, I'm fish sitting for a friend who's traveling for the holidays. I went over last night to feed his fish, and noticed some very strange growths/protrusions from his large Jack Dempsey's head. I called my friend and he says he's seen it. He thought the fish swam into the wall and cracked his head..... I didn't argue because I'm no expert, and they're not my fish, but if you all could help my identify the problem, I'd like to try and take care of it for him. I'm attaching a pic. I hope it's clear enough to identify the issue.

Thanks for any help!
- John


Sent from my iPhone using MonsterAquariaNetwork app

Little bump for some insight. Any help is always appreciated.

- John


Sent from my iPhone using MonsterAquariaNetwork app

Appreciated! I've never had a fish with hole-in-the-head before so I wasn't sure what I was looking at here. I'll start treatment tonight.

thanks again