Leaning more and more towards lymphocystis. I think there is now a bump on his body by his anal fin, another bump in his mouth, and a bump between the two bumps you can see in above picture. The white part fell off and all that is left are two pink lumps.
I've been dealing with lymphocystis for some time in my tank. The fish can eventually get over it and build up an immunity to the virus so future outbreaks aren't as bad. The problem with your fish is that the sores are so close to its gills. If It does spread to the gills than the chances of recovery go down. There's really nothing you can treat it with because there's no cure, but keeping stress to a minimum should help. I've read that stress is a big contributor to these kind of outbreaks. So make sure the water is clean, add some salt and make sure it's not getting bullied by tank mates.