Using burnt utensils?

I just accidentally cut my hand with a knife, in an attempt to disinfect the knife, I hold it over the fire, then the knife's edge turned brown, I put it under water and it sizzled, disinfected, but the knife remained brown, I wonder if it's ok to still use the knife. Is it gonna be poisonous?

Burn mark won't come off if it's stainless steel.
As far as I know, it's not poisonous...but don't take my word on that lulz.