Thanks for the query.
If you are sure it is sunburn
, visit to doctor is not required.
you can apply some topical steroid
This will help in healing the lesion.
Once it is healed you can apply sun screen on daily basis.
Sun screen can prevent sun burn but cannot cure it, hence steroid is required.
Let me know if you have any other doubt.
you can ask a direct question to me on this forum, following the below link.