Hello,
Halo nevus are benign lesions and hence nothing is to be done for them . they should be left as such. However sunscreen should be applied to all the skin during summer to prevent sunburn. The white skin of a halo naevus will burn particularly easily in the sun.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.