Massive sympathy coming from here!! I am massively paranoid about this because my DH travels a lot but he's the sort of person who wouldn't notice/react to the bites so I would be the person who gets the full force of it. If that were me, I would get your home treated professionally, vacuum like a maniac (especially in any of the suspect areas & nooks & crannies) and hot wash & dryer every last shred of bedding (including any thing that might've been stored/in cupboards with the suspect bedding.

On the positive side, you know what you're dealing with now & you know not to accept any more donations from your friend!!