KMC Forums - Sabretooth Question

I've recently been reading some of Sabretooth's early pre-X-Men appearances in Iron Fist, Heroes for Hire, Spider-Man, and Ms. Marvel. One thing that's obvious is that up until Mutant Massacre, he was not intended to have a healing factor as he's sent to the hospital for extended stays by Misty Knight and Black Cat.

My question is, was there ever an in-universe explanation for this? The only indication that he has a healing factor in these early issue is that Black Cat rips open his face stitches (his face was torn apart by spider-man's webbing and then stitched up into a tapestry) and then pounds his head, face first into the asphalt repeatedly until it's a mess but then he is fine in Ms. Marvel.

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