Is this a bite, scratch or something else?

[Gilead]

Noticed it this morning, there’s a definite hole in the middle but not round more a tiny slit! Not sore or painful to touch.
Any ideas?

Well, if it's appeared over night, it could be either. I would guess a bite that had been scratched. It looks like it has healed around the edges.

I have a similar scratch on my arm which I received at a plant exchange 12 days ago which has not improved at all. I think it was a cactus and it has caused an allergic reaction. A bit of cortisone cream should help but I have just left it to heal on its own. Could that be what you have OP?
Perhaps ask a pharmacy for a treatment.

thought it was an allergy at first but the hole put paid to that idea; however, I’m a psoriasis sufferer and happen to have cortisone cream handy, thanks for the suggestion!