Some kind of rash on my elbow, underarm and back of my neck it is bumpy and skin colored. when you scratch it a lot and over time, it will get tougher and the area appears to be pink. if i keep scratching and scratching until it bleeds, it will become dry

This : This really does sound like eczema. That was my first thought before i even read your doctor's diagnosis. You could also be dealing with a dermatitis, due to an allergy. I recommend you request allergy testing or blood testing (check with your doctor regarding prices), and also a higher strength triamcinolone cream or another steroid cream like Elocon is good. Keep the areas hydrated. Use vaseline, aquaphor, or eucerin cream (in a jar). Good luck.

Unsure: This rash would likely need to be examined and more history obtained to be able to provide you with useful input about the diagnosis or possible treatment.