Its difficult to fully evaluate from your picture. The site appears to be healing for only 2 days out. The white/yellow area may be caused from too much pressure if you are wearing a temporary flipper over the area. If this is the case it may need to be adjusted, and you should keep it out until you see your dentist. The black area may just be your blood clot or if a laser was used during the surgery it can often make the gums appear black and scabbed. Call your dentist to discuss it.