Hi there. Please do check your bed & bedding materials & vicinity. It appears to be some sort of insect bite reaction to bed bugs/ fleas/ dust mites on your bedding materials/quilt /surroundings. You may want to use an insecticide in the area & keep all your bedding et al in the SUN to air for awhile as also be vigilant with your laundry. For the skin lesion per se, try to use a topical hydrocortisone-salicylic acid
3% combination cream on the spot twice/daily for 2-3 days. Hope this helps. If not, do visit your local dermatologist
for a hands-on advice.cheers!