Maddie has one of these as well, hers has hair growing out of it. We aspirated it and that is how we found out it is a cyst. I refused to put her under anethesia just for this. Vet told me to keep an eye on it and if it grows any bigger she will need to have it removed, it has not grown but it did help to find out what it is. I did ask an aminal communicator to ask Maddie if it bother her and Maddie's response was "No Mommy it is not bothering me, it will pop on it's on and will go away. I am still waiting for it to pop Maddie/
Get it checked out Anne for your peace of mind. Hugs to you and your boy