Your first step is getting in with a specialist. There are many all around the United States. Due to the location it may indicate that there are airway hemangiomas as well. He also should be screened for PHACES. You son will probably be started on steroids to control the growth. Your Pediatrician may even be able to start him on the steroids. There are side effects from the steroids but the benefits usually outweigh them. There is medicine to help with the tummy issues some get from being on them. Keeping it small will help it go away faster later.
My daughter is 4 and had a large H that stretched from her rt ear to her chin, neck, lower lip, mouth, tongue, with spots on her lt ear, chest, rt nipple, rt side. She was on the steroids for a year and then we watched and waited for 18 months and then we started laser at age 2-1/2. She has had lip reconstruction surgery done to fix the ulcer scar and remove excess tissue from her lip. To date she has had 7 lasers.