Before other responses come in, you might be interested in the previous answers to questions related to the protection from sunburn in the past, such as:

Sunburn and Roman remedies for it as described by Pliny were mentioned in this thread by u/RexSueciae

Medieval remedies for the sunburn, some of ancient origins were explored in this thread by u/sunagainstgold.

Input concerning practices in ancient Egypt and medieval France can be found in this thread by u/waspocracy and u/grantimatter.

And last by not least, you might some information about actual relation between sun exposure, sunburn and skin cancer in my previous response to a similar question.