What was this lump on my dog's neck?(Besides gross, that is)

If you can afford the vet visit I would at least get her on some antibiotics. It sounds like some kind of infection.

Most likely an abscess. She might need to have it cleaned, drained and an antibiotic. You need to try to keep it open and draining with hot compresses, squeezing it gently and using an antibiotic ointment or betadine flush.

Personally, I’d take her to the vet for a check on it.

That’s just it though; the skin wasn’t broken, there was no injury… more like something was blocked. Really kind of a giant zit. I certainly will take her to the vet if I need to, I just prefer to try to take care of non-serious things myself if possible. (I had a dog who was prone to hot spots, and I would have gone broke taking him to the vet every time; I learned how to nip it in the bud after a couple of them.)
I know that now that the skin is broken, infection is a possibility, so I will be keeping a very close watch. I will be sitting on the floor with her later, holding a hot, damp cloth on it and bribing her to cooperate with tidbits.

It’s an abcess. Get the pup to the vet, have them clean it out and put her on antibiotics. They will most likely also fill it full of something like betadine and pack it, then bandage it to keep the dirt out. Left untreated, the pup could become quite sick. Don’t wait any longer.

Im also going to say absess. My dog had a lump it felt like a rock on his back. It never turned like what you describe this as, my dogs was carcinoma apparently! He had it surgically removed when he got fixed. Good luck with your dog.

Often here, dogs will get grass seeds under their skin. It can cause a zit like pustule. When they come to a head the pressure is released and they usually heal on their own. I hate antibiotics and my dogs don’t like going to the vet so I don’t go unless it is absolutely necessary. I would monitor the pup’s temp and in the meantime bathe the area with epsom salts compresses a couple of times a day. If it doesn’t appear to be getting better in a couple of days, then I would head for the vet. Temp is an excellent indicator of infection.

I think @DreamTrees nailed it and I agree with the recommendation. I had a cat with a similar situation once and, if the actual space where the “junk” used to be is very big, the vet will want to pack it so that it can heal properly from the bottom up. Otherwise, the top (skin) heals and it refills and can become a chronic situation.

Update: have done the moist heat thing on the spot, it’s looking good and staying flat:-) Continuing to monitor and apply the damp, nuked washcloth. She is getting impatient with the whole thing.

Ahahaha! I laughed at this one..
“What is it? Boil? Sebaceous cyst? Alien??”

But then I remember my first panic with this kind of problem.
My japanese chin had the same problem.. being a noob in taking care of puppies, I rushed to my vet’s clinic. So wonderful these days, answers can be attained with a blink of an eye.