Ive had this happen on one of my Kershaw clips before, i ended up getting a small slotted screwdriver(i believe it was a 1.5mm) that would fit inside the stripped head and was able to get it out that way. I emailed Kershaw and within a week they sent me new screws and a new clip even though it was fine.
Jimmer_5 was right though, get a good Wiha or Wera driver and you probably wont have these problems
Jimmer_5 was right though, get a good Wiha or Wera driver and you probably wont have these problems