Physical exams are recommended every 6 months. Hedgehogs are not routinely spayed or neutered. Mites are an external parasite and can cause systemic illness. They live at the base of spines and may be difficult to visualize. If mites are a problem, change bedding to a paper product, clean the environment at least weekly, and dispose of all cage furniture that is porous.
Mites are extremely difficult to treat.
Contact your veterinarian if you suspect mites as there is an injectable product that is effective against mites. Monitor water intake, appetite, activity level, fecal and urine production. If anything worries you, or changes from normal, contact your veterinarian.