Using either of the nVidia AI Denoiser 2.3 or the Intel Denoiser 1.1 i'm getting this error which just repats until it finally creates a 0 KB png file.
I do use Photoshop to remove certain imperfections.
The Character's arm textures likely got messed up somehow. I've had this happen sometimes when using Skin Builder (rare but sometimes something goes wrong and the textures get altered). Is that tattoo part of that character or did you add it from another source. Sometimes Tattoo's aren't L.I.E, or even an Overlay, but character specific so when you add the tattoo, you're not just getting it, but that characters skin for that tattoo's location (Torso, Face, Legs, Arms). In that image though it looks like only the Arm textures don't match.