My boyfriends brother stayed with us for about two months and left about a month ago. he had a rash and was constantly digging and about the time he left we both got it. looks like a heat rash but now i am getting blister like bumps on my hands and feet a

Scabies: Sounds like you may have scabies, which is a microscopic mite. Go in to see your doctor so he can diagnose and treat you?

Could be fungus: Get checked to determine what kind of skin condition you have. There's a possibility that you have picked up a fungus. If he was picking at his rash, it had the possibility of spreading and all you needed was a small break in your skin to pick it up. Fungus is everywhere, it's just whether you have the skin intact to prevent from contracting it. Go to the doc.

Also, disinfect : Once treated, the key to prevent re-infection is disinfection. Not only disinfect/clean the area where the rash is, but think of the inanimate things as well, the floor and the shoes you wear.