Still have stitches 6 weeks pp?

I have one stitch that STILL hasn’t dissolved. I’m so annoyed. Had an appointment at 4 weeks pp and doctor said everything was fine and healed and won’t have another appointment. Apparently my doctor doesn’t do 6 week appointments 🙄 how am I supposed to know when it’s okay to have sex if I still have a stitch?? When did yours dissolve?