Several options. One of the simplest options is to get apple cider vinegar and apply it liberally to dry hair daily for a week. Then shampoo hair. It often kills the bugs and dissolves the glue holding eggs to hair. Otc products like nix (permethrin) are mild bug toxins & are used the same way. & come in a kit with a special comb to help remove the eggs. Your physician can prescribe something if needed.
Several options. All pharmacies carry a variety of effective products. A key is clearing all nits out of the hair with a nit comb. If the problem continues, there are prescription products your primary health care provider can provide and they may require an office visit.