Scar on face
If this only happened 4 days ago it is likely not a "scar" already. Superficial burns on the face heal quite well in general. I recommend cleaning the area daily with warm soapy water. Follow this with a silicone based gel or cream which will help to hydrate the tissues, decrease redness, and help to optimize the healing of your burn. It is also very important to apply a high quality sun block with at least spf 30. This will help to decrease the chances of hyperpigmentation. Best of luck!
Plato's Scar Serum and Melarase creams
Conservative treatments are best at this point. I would begin with Plato's Scar Serum and Melarase followed by fractional laser if needed.