How do you sooth extremely itchy sunburn?

Salve: Applying aloe vera can help. You may benefit more from salves that have Hydrocortisone in them. There are other otc treatments that have some numbing medicine in them as well. At night you might want to take an antihistamine to allow you to have better rest. You may need to see your doctor if you aren't getting any relief. Make sure you rehydrate your skin w/ water & emollients that absorbs well.

Lots of cream: Apply creams or ointments liberally. The heavier the better. Putting on damp skin makes application easier. Lotions are second best to creams and ointments.