Red bump

Hello, I have a 4 month old puppy, she’s a Chihuahua and I just got her a week ago , and I’ve noticed that she was loosing hair around her eyes , ears and mouth, first I thought that it was due to the stress of being on an airplane, then i thought it could be mange so I i took her to the vet and she gave her Vitamins, omega 3 to take daily but now she has a red bump and I totally freaked out because i have no idea what it its, could it ve allergies? 

Hello.   I think that you need to get this lovely girl checked out by a vet.  Hair-loss in puppies can be classified into one of two groups:  itchy or non-itchy, and the two groups have very different causes.   Itchy hair-loss tends to be connected to either allergy or parasites (mites, harvest mites, fleas).  Non-itchy hair-loss tends to be connected to hormonal  (endocrine) dysfunction - especially when it is symmetrical - or autoimmune disease, but can also be due to a different, non-itchy type of parasite known as the Demodex mite.  Demodex is relatively quick and easy / non-invasive for a vet to test for and is also common in puppies with low immune systems / under-going stress.   I'm afraid that the picture is blurry and I am unable to tell what the orange lesions are;  I do wonder whether harvest mites, or simply scratches to the skin, or leakage from the ears, may be possible?      Either way, please do take this pup to the vets so that they can do the tests necessary in order to narrow down the possibilities from here. When they know the correct cause of the problem, they will be able to help to suggest a remedy.