First place I would look is in the resource section above to see if there is a doctor in your area. This doctors are who others have recommended and have used in the past.
Being that your son is 13 the condition is probably not a hemangioma being that most hemangiomas go away while a person is a child. Most doctors call them hamangiomas because they are not educated enough in this field. It could be several things but I am not a doctor and could not diagnoise him with something.
If you can not find a doctor in your area. You can go to the front page and send a message to the Ask the surgeon Dr. Levinten works with Dr. Waner who is my plastic surgeon. If you sent him a picture and discribe what it looks like, feels, and size he might be able to give you his opinion on how to treat it. Dr. Levinten has a daughter who had a hemangioma removed from Dr. Waner before they became partners so at a personal level he does understand what you are going thru. They are located in NY and are in the section I mentioned if you would like contact info for an appointment.
Or if you live on the West coast there is a specialist in Southern CA who is also in that section I mentioned.
If you are unable to find a place near you and are unable to make it to either of this other places let us know what state you live in and someone might know of a doctor in your area they can recommend that is not on the list of doctors.
I hope this helps and if you have any other questions please ask everybody on this group is here for you.