I doubt if it is acne. Round patches of hair coming out could possibly be ringworm (?) This is also called Scabies, and is transmissible to humans, so veterinary treatment is advised.
It is not caused by a worm at all, but by a fungus, and can be picked up from the earth, the soil. It is quite common.
Here are some pictures and info:
Or if you prefer, put "Ringworm dogs pictures" into google search and see if any of the pictures look like what is happening with your dog.
Another possibility (which is hard to tell without seeing your dog) -is demodectic mange. This is also quite common, and is treatable.
The best thing to do is to take her to the vet and see what they say, and what treatment is advised.
If vets' offices are closed already for the Christmas holiday, then take her as soon as you can when they re-open. It's not an emergency situation, but it's best not to leave it too long.
In the meantime you don't have to avoid her! Just make sure you wash your hands thoroughly after you have petted or touched her.