Are there any other white bumps?
White bumps on the mouth are very different from white bumps on the body. For example, bumps on the mouth can point to thyroid issues. Don't start treatment until you know what it is.
Look into Lymphocystis ...
I see live plants. Salt will stress and kill them.
If it is Lympho it can go away on its own or maybe never get any worse.
Most pics and stuff on links are the worst case scenario. I wouldn't worry, just keep an eye on it to see if some other symptom shows or if it gets worse.
The fish does otherwise look very healthy.