I had a labiaplasty 6 days ago but my bruising seems to have only appeared from day 4. Is this normal?

You have bruising with minimal swelling. This suggests that you do not have a hematoma. You should heal just fine and your bruises should resolve in a few weeks.

Congrats on the surgery  the results look good.... but then again it is only your opinion that matters at this point.  Your healing is normal.  Relax and enjoy the new you.