Platy has strange bump

My platy has had I strange bump on its head for a while now I am not sure what it is. It is in a quarantine tank right now that is ten gallons.

Ammonia .25 ( I have been doing 50% water changes every day)

Nitrite 0

Nitrate 0

Ph 7

 

How long is "awhile"?
It might be a tumor, though I'm not sure.

 

A year at this point.

 

A year at this point.

Hmm. It probably isn't dangerous then. Have you noticed any strange behaviors?

 

No, it seems normal. But it does seem to have gotten bigger. I will put one picture from a while ago I and one from today.

 

I tried using neoplex and it seemed to work. However we ran out and when I got it again it did not do anything.

 

How do I know if it is a tumor