Mild excema 15 months old babygirl

Naty
Hi beautiful and brave mommies, 
I need an advice regarding baby eczema. My daughter is 15 months old and she have a white coin size white spot on her right arm. Ive noticed it when she was around 9 months, ive applied vaseline but it seems that it doesnt go away. Now we are in summer and we are outdoors more often i started noticing small white dots from the sun too. The doctor told me is very mild and eventually will go away but i was wondering if somebody have experiencing with this amd what did you applied. Ive heard to shower her with  "selsun blue" will take it away. Any suggestions?? I will appreciate:).