small open holes in my cats skin

My cat is an indoor cat, but does go out on the balcony and now has 2 small puncture looking open wound looking holes and I don't know why.  

Hello!  Obviously I can't see this wound and nor do I know the position on the body or the size of the holes, but from what little I do know, if your cat went out then a bite wound might be towards the top of my list of possibilities.  Other cats and rodents might be the main causes of such lesions indoors, depending on the house.  I wonder about a foreign-body entry then exit?  (Grass seed?  Likely not a pellet gun indoors)  Self-trauma?  Fly / flea bites?  Lick damage (shallow, surface lesions)?  However, my speculations aren't very helpful - to move the case forward, it sounds important to find out what this actually is and a veterinary appointment may help to get the ball rolling.  If you are not sure how urgently you need to be seen, they may help by triaging the case over the phone.  Please do let us know what happens next!