CQB injuries... interesting.
I have not had to deal with anything too serious at CQB, the majority of stuff being either soft tissue injuries or minor musculoskeletal stuff
Here is a run-down of what I have seen / had to deal with (or had) and my suggestions on how to avoid similar happening in the future:
BB's lodged in various soft tissue (chins, noses, ears) - wear full face protection and a hat that covers areas likes foreheads, etc.
Cracked teeth - gum shields / full face pro
Abrasions to knuckles, elbows, knees - wear appropriate gloves, elbow and knee protection
Minor burns to hands - don't pick up pyros to throw them back, or wear gloves when striking pyros / hold pyro so when it lights it doesn't burn your hand!
Banged heads from running into things - wear suitable head protection (fast attack helmets)
Temporary tinnitus from flash-bang - ideally, ear defenders (Peltor Active Ears) but these are expensive.
Twisted ankles - good footwear that supports ankles.
I think that is about it off the top of my head...
Oh, and I won't be admitting to the ones I have suffered from personally