Like freewill suggested you can use a damp cloth to help hydrate your skin. You can even soak it in cool milk as the lactic acid will help heal your skin. Keep yourself hydrated to help the healing processes of your skin.

You want sunscreen that protects against UVA, UVB and is higher than 15.

Water resistant is good too.

If you are worried about Skin Cancer there is some controversy over the use of sunscreen. The types that absorb the filter into your skin can actually be a contributing factor to the most prominent type of skin cancer---which is not caused by sunburn.

For this reason I don't use sunscreen. I live near the beach and having a tan is just something I like lol.