I’d sooner suspect fur mites (cheyletiella mites) than lice. But they can also have a bit of dandruff when they molt.
With fur mites you often see some localized fur loss, and on the hairless patches there are often white or yellow-white crusts that can’t be removed with your fingers – the rabbit will react with pain if you try to. Some bunnies get an itch, but others don’t.

Fur mites are very treatable and the best treatment is Revolution (selamectin) or ivermectin. In most places you’ll need a vet to prescribe those meds. Repeat treatment after a couple of weeks is recommended. These meds will kill other parasites as well, like lice and fleas. 

Whenever anyone mentions possible parasites on a bun, we always issue a warning against using fipronil. Fipronil is sold under many names, for example Frontline, Sentry and Effipro. Fipronil is deadly toxic to rabbits. It kills mites, but it might very well also kill the rabbit. (Reports of tragic incidents here have made us alwyas issue this warning.)

Here’s a picture and a description of what fur mites might look like. http://binkyabout.com/mite-infestations-and-rabbits/
You’ll find more lots pictures if you google. Fur mites are very common in rabbits.

Meanwhile you can brush your bun, it helps get mites off and can be a relief for the bun. If there are actual sores, treat them like you would any other sores (triple antibiotic cream without a painkiller can be used on a bun).