I cannot help on the spot either my yorkie definitly snorts mostly when hes excited alot of yorkies do ! My moms yorkie snorts all the time ! 

  Its part of her charm The itching i can help with Maybe, im a groomer I just attended a seminar on bathing and skin care Ask your groomer what kind of shampoo she uses The less ingredients the better And it is very important all the shampoo gets rinsed off that alone can cause itchy skin also Also Eveyone is so right on the nutrition I can recommend one called solid gold the puppy one is called wee bits I will be selling it in my shop Ive seen the advantages of it They have literature you can read up on also But # 1 !! Find a new vet ASAP they shoould not hurry you and send you home with questions if you like your groomer ask who she recommends or other pet owners you run into ask who they have alot of confidence in worrying about your yorkie can consume your life I know first hand One vet told me my babyboy had a tumor , A second opinion told me he had an absess tooth big difference SCARY ! Also im a member of groomers lounge .com there is alot of info and knowledgable groomers on there who may have seen that mark and know what it is Find a new vet right away ! they sound horrible you will find one that spends time and cares Goodluck your baby is adorable !