Whatever other treatment you try, also consider the dog food you are feeding. Allergy to corn is commonly demonstrated by "mange-like" symptoms of hair loss, tissue swelling (especially around the toes), open sores, weeping skin.
Use a food without corn. Corn passes through the system almost unchanged. It is a cheap filler dog food companies use to save money and it causes digestive and skin problems.
She goes in next week for her shots, the other thing that makes it strange is that when we got her (couple of weeks ago) she had very little fur on her under belly and under her arms now its grown and those areas arnt dry or anything and the fur isn't thinning its getting thicker.
You need to take the puppy to a veterinarian about this, since its a continuing problem. She could have mites or mange, and you can't treat this on your own. She should be going anyway for her shots, so get some expert help with this.