Not an expert, but after searching, I think it might be head lice? I'm probably wrong, but here's a photo
Mosquito bite like bumps red around it appearing on my skin randomly usually only at night, itchy. See nothing on bed or body?
Could be a number of things .. From bug bites (bed bugs?) to an alergic reaction to creams, soaps your using on your skin .. Or even fabric from your night clothes or bedding
Could be eczema or more precisely contact dermatitis.