Sunburns only affect the skin's outermost layer. So the scalp's outer layer takes most of the pain and suffering. But hair growth isn't something that only happens on the surface.
Sunburn has little effect on hair development and loss since it does not directly harm hair follicles. Therefore, a burnt scalp is not caused alarm regarding potential hair loss. In addition, you shouldn't worry if sunburn causes temporary hair loss. Your hair will grow normally after your scalp has recovered.