Freezer burn
From Halopedia, the Halo wiki
'Freezer Burn', as it is known throughout the UNSC, is a painful injury sustained while being covered (clothes, towels etc.) during cyrosleep. Clothed skin tended to react badly to the cryotube process, resulting in some 'pretty nasty rashes'. This is the reason that most personnel go into Cryosleep naked.
Quotes:
"The SPARTAN's skin must have hurt like hell"..... (Sam Marcus)
