Bitter taste in mouth after tooth extraction/bone graft.still have it 4 weeks later.dr says tooth looks great and taste is not from that. thoughts?

Bitter taste: Bitter taste in the mouth can be from all sorts of causes. Merely listing them won't really help you. Did you ask your own dentist what he/she thinks are the possibilities even if it's not from the extraction? Did you ask if you should consult with your own physician? You need to be evaluate by both a physician and a dentist to figure this out for you.