I have had an intense itch on my arms resulting in a bump then a sore for 6-8 weeks now. It is only on my arms and my left is way worse. My right is only on the front shoulder. I have been to the doctor and dermatologist they gave me steroids ( a shot and cream) neither have helped. They did a biopsy and claims it came back just a thickening of the skin because I pick at it but that doesn't explain the itch in the first place. Any ideas?