My fish is at it again

[Spoiled]

My fish is better now, but three days ago the bump on his chin reapeared, and he was very bloated.

Could something be fataly wrong with him?
Is something medicaly wrong with him?
Why does it keep reapearing?
Is there anything I can do to stop it from happening again?
I shouldn't change his food, should I?
Should I just stop feeding him durring this time (about two to three days) like I did this time it happened? He isn't eating anyways, and doesn't seem to be able to.
Will it keep reapearing?
Will he not pass through it one of these times?
Why does it not affect my algae eater?

Sorry for all the questions. I'm just so worried about him, and I want and need an answer for these.

This afternoon was the first time he ate in a while now. The bump is gone from his chin and the bloating is also gone.