With my babies I go running to the vet for any lump, I thought in the beginning that he would think I was crazy ... but he then told me that it is best to check out any lump. I would suggest that a trip to your friends vet is your best bet.
It does sound like an abscess to me. The vet may just drain it, and apply antiseptic, and probably give you some to keep bathing it with (it will be important to keep the wound open until it is fully drained) Or, like Misfits4Me said, a course of oral antibiotic may be necessary. My dog had an abscess on her back a while ago, and the vet drained it and washed it out with antiseptic, which I then had to do 3 times a day and allow the wound full drainage to stop it filling up again. The hole it left looked pretty gruesome, but it healed up just fine and didn't take long.
Obviously keep dirt out of the wound, but don't cover it unless the vet advises you to.
It could also possibly be an infected cyst. In which case the vet may suggest having it removed so there's no recurrence of this.
Hello....If the lump is actually on the neck, it sounds like an infected abscess....They are extremely painful! She (The dog) needs to see a Vet to have it drained......Oral antibiotics are needed to keep the infection from spreading into the system, from the toxins......
If the lump is farther down between the shoulder blades, then you may be dealing with something completely different......Tumors are prone to that area & it needs to be removed quickly......
Either way, this little girl needs to get some medical attention.....Please don't wait as both of these cases will only get worse on their own......Karla