James has hit the nail on the head. A zinc-based sunblock without any irritants or oils is the ideal solution. Be wary of a lot of the over the counter products and read the ingredients. Avoid ones with coconut oils, parafin oils, etc.
One product that I have been using to good effect is Gala’s Ombra Creame ™. It is a total sunblock and is intended to be applied directly after electrolysis. As it is has a light pigmentation, apply a small amount with clean hands on clean skin and spread it out until you do not see it any more. A little goes a long way.
This product is available from Dectro Int’l.
Toll Free: 1.888.332.8763
Orlando Institute of Electrology
Associated Health & Beauty Products
Toll Free: 1.800.548.6339
I use this product both on myself, post treatments, and on my clients as well. So far I haven’t had any problems with it in either case.