Pentalobe screws just spinning!

Hello

Recently repaired a friends iPhones 5s. Initially was getting no service after repair and updating iOS appeared to resolve. Then phone died when testing, though all appeared okay so popped on charge.

After changing, received the reboot and blue screen of death. Attempted to update iOS via iTunes to no avail.

Assume two of the screws on the top right panel are wrong way round. Problem is the two pentalobe screws now won't come out - they're just spinning in place! I'm relatively sure that if we got those back out we could swap the screws back and all would be fine but just stuck at this point.

Has anyone had any similar problems with the pentalobes and if so, what did you do? Not keen on drilling as never done before but might have to at this rate!

Thanks in advance for any advice!

Cheers, J.