Bonded tooth turning brown at the margin line. What options do I have? (Photos)

I bonded a small gap between my front teeth 4 years ago, but recently I noticed it started to turn brown. It used to be just a small brown dot, but now the entire margin line is dark. It doesn't hurt, but the line is slightly rough when I touch it with my nail. I do drink tea and wine occasionally, but I always try to brush afterwards. My question is if it's a stain that can be polished or do I need it replaced? I can't see a dentist until 3 weeks. Thanks!