what’s wrong with my tetra

my tetra has had this growth on his lip for a few weeks now and i’m not sure what it is i thought it was a parasite at first as i recently had to deal with that problem in my tank, but i dosed my tank and it’s all gone now but that lump still remains on his mouth does anyone have any idea what it is ? i’m not sure if it’s getting bigger or not i feel like it is but that could just be me over thinking it