Dark black triangles after braces, would a gum graft fix this? (Photo)

I have noticed that I have dark triangles for awhile but 2 days ago I just had my braces taken off. I asked my orthodontist if she could do anything to fix it but she said she wouldn't recommend anything such as IPR or bonding because nobody's going to see the dark triangles. Basically she just told me to chill. But I don't feel confident at all and they bother me a lot. Would a gum graft work for this? Or did there ever happen to be a case that the gum could regrow to close the holes by itself.