Sunburn, frostbite or underwatering? how to help?

[cecilseed]

I bought a pack of 20 succulents that were delivered over mail this week to New Jersey. It was pretty warm out over the weekend and most of them came out fine. This one I don't remember being damaged and scabbed but I was so excited I might not have noticed. They were losing soil so I repotted them in bigger group pots, being sure to loosen the roots. They got half a days worth of north window sunlight next to a fairly cool window. This morning I noticed this hard scabbing over the edge of some of the leaves. I watered all of them for the first time this morning. Should I take it out of the sun? Quarantine for infection?

[greenknight]

Frost damage is very possible, they can't take a hard freeze. Not likely underwatering, it should be kept dry in the winter. Not sunburn either.