Hi, There Is Something Biting My Husband At Night While

Hi, There is something biting my husband at night while he sleeps. He wakes up with small red, itchy spots that welt a little after he scratches them. They last a couple of days. I have had the bedding changed, the whole house sprayed for insects. (inside and out). Sometimes he tells me it feels like something is crawling on his skin. I am not sure what to do....