It could be irritated from a bug bite or just a scuff from rubbing on somthing. i would just give it a clean and keep an eye on it.
I would also urge you to get rid of the chippings as they can cause impaction and mouth injuries.
Are you asking about the brown coloration behind her eye? My best guess would be a bite but if you're sure its not then I'd assume its a scratch or discoloration from something in her tank. Wood chips can be rough on their skin and can cause injuries. Other than that I'm stumped.
Actually this time it's quite different, and weirder! It's shiny under light, looks like gold dust..?! Rubbing/Scratching it makes nothing... It's been here for a month at least. This gecko had a fight indeed but it was bitten on it's back (you still see the scar) NEVER on the had. Could a simple sign of post fight stress?
Yes, the first pic is an old one, this second pic is NOW. I just checked what's "Paradox". If it was that, it should've been here for long; it's not the case, it appeared VERY recently.
It looks like a scrape or a bite or something. I've seen similar things on my geckos before. The scrapes almost look like they're leaking a plasma of some type similar to cuts on humans. When my geckos get scrapes like this I actually just use a bit of polysporin/neosporin on the end of a q-tip and dab some on the wound. I'll do that for a few days until it looks like the wound is drying up or healing. The marks disappear after their next shed usually. That had been my experiences so far but I'm not a vet