Strange wound on cat.

I just noticed this little wound where my cat's collars usually rests. I shaved the fur around it to get a better look.

Hello - I feel I'm missing a bit of the story here.  Where is the collar?  Did you cut the fur or is that a ring of pressure damage from the collar?  Did you find this underneath it, or was the collar off for another reason when you noticed it?  Depending on how I look at my phonescreen, I see a pressure sore, an allergic skin reaction, an insect bite, or a growth which could be benign or cancerous eg a squashed papilloma or a mast cell tumour.   With lumps, the devil is in the tissue it's made from not the outer appearance;  this can be seen on biopsy.  Sometimes an insect bite or where the skin has been 'caught,' would just resolve while you were waiting for the appointment.  However, I like to get things checked out.