I thought it was a tick

It is a microdermal implant which gives her Master control over her every movement and thought. When The master sends a text "Evacuate Your Bowels and Bark Like a Bitch Dog" ... well, you know what happens. These implants, however, are subject to being taken over by remote control, especially if The Master used a password like "password". I'm presently working on a very long range device to capture the control system of this female creature and order her "Put on a Burka Now Slave Woman but you will be naked underneath with a 220 volt 10 inch vibrating dildo in both orifices of your nether regions."

Or something like that.

It's probably benign and removing it would leave a big scar. I've had some of mine removed.