Hi! I would definitely see if you could get in with a vascular anomalies doctor or pediatric dermatologist, someone who sees these things all the time. You could tell your pediatrician that since it is on his lip you would like to make sure it is correctly diagnosed and monitored in case any issues come up (since lips can be prone to ulceration, etc.) I would also suggest taking photos of it on a regular basis to document any growth or changes. I found that to be very helpful and I know that doctors we have shown found it helpful too. Keep us posted! Your son is adorable!!!!