Bump on my 3-month-old puppy's head, no idea how it got there?

This could just be a normal formation of your dog skull. If it is not getting bigger, does not feel like it has fluid in it and there is no discharge I would recommend just measuring it once a day for about a week and seeing if it truly is getting bigger or not. If it is not it's likely a normal skull developing. If it is getting bigger then have your veterinarian take a look.

The bumps could be an allergic dermatitis from fleas, insect bites, etc. It could also be a bacterial infection, even if you aren't seeing any purulent material. You could bathe him with a dog shampoo, like Epi-soothe, and see if that helps. Otherwise, he should be seen by a vet for treatment. He may need an antibiotic, anti-histamine, corticosteroid, of other medication to help.

Your puppy is plenty old enough to get started on her vaccinations, so taking her to the vet shouldn't be a problem. If she's acting fine and the bump is improving, then I wouldn't worry about it too much. She may have just banged herself hard enough to get a swelling. If she isn't acting like herself, then I recommend getting her to see the vet right away.

Hi I can see the swelling on Deijah's head. There are a few possibilities in a young dog : could she have bumped her head and now has a bruise swelling? Some skin cysts can look like this also. occasionally I see spider bites that develop into abscesses that can appear quickly. Does she seem painful when it is touched? If it's not going down in 1or2 days, you should take her to your vet for an exam.

A bump can be any number of things from an insect bite to infection/abscess, cyst or adnormal growth. If it is growing rapidly, is painful or changes in color or size quickly I would have Skookum checked by a vet.

First, great pictures and highlighting of the lump! This appears to be a fluid-filled lump. Usually puppies get these when they bang their head on something and then fluid accumulated under the skin. However, I do worry about congenital defects that could cause accumulation of CNS fluid under the skin. If Thor is otherwise acting and looking normal, then either way, it's not an emergency. If he is acting weird, then best to have a veterinarian check him out. If it was just a bump, then the swelling will start going down within a couple of days. If it continues to grow, then it would be concerning enough to make an appointment with a vet. An easy way to detect growth or shrinking is to draw around the edge to the swelling with a magic marker. It will look silly, but it's really easy to tell if the border of the swelling has moved. I hope this helps.

Head trauma is always a cause for concern. Since this happened yesterday, there should have been some improvement with your pup if he suffered an injury such as a mild concussion. Sleeping a lot is not so much of a concern since young puppies normally sleep most of the day, but if you also see signs such as unresponsiveness, a head tilt, circling while walking, unequal pupil size, twitching of the eyes, ataxia (wobbly gait) or [vomiting](https://www.petcoach.co/dog/condition/vomiting-1/) then he should be [seen by a veterinarian immediately](https://www.petcoach.co/article/how-to-handle-a-pet-emergency/). If there is a bump, it may be a seroma (blood filled sac). This can treated by your veterinarian by either draining the area or trying a veterinary anti-inflammatory medication. Do not medicate him with anything OTC without the advice of your veterinarian as [many OTC drugs can be toxic](https://www.petcoach.co/article/7-human-medications-that-are-dangerous-for-your-pet) to dogs.