How to get rid of these mosquito bites?

My son has had these mosquito bites for about a year now from June of 2010 from our vacation in the Philippines. He has these brown scar's around his legs with all of them being very dark, and there is this one big welt one around the side of his right knee cap which is swollen compared to all the rest that are just brown spots. So how can i get rid of these brown spots and that swollen brown mosquito bite near his knee cap. Or should i see a doctor because its been a year now and i though that they would go away but he still has them. But he says that they don't itch, only that they look annoying, so please give me any suggestion on how to deal with this and thank you.