My first thought was it was just a scab from a bite. Wooly had some little scabs on his back from Leopold. I didn’t even know they were there until we were at the vet for something else and I saw them there.
If it is a bug and it is under the skin, then that is likely the head of a tick. The body probably got pulled off and the head was left stuck in the skin. That’s why they always tell people to grasp them down by the head with tweezers when removing them. Otherwise you will have a tick’s head stuck in your skin and it can get infected.
If that is what it is, I’m not sure if you will be able to hold your bun still enough to get it out. When it is on a person, they tell you to put alcohol on a cotton ball and rub it over the area. This loosens the mouth parts that are “glued” into place. Then you have to use a needle to work it out far enough to grab it with tweezers.
This may be something a vet needs to do.