Suggest Treatment For Red Rash In The Arm Along With Numbness

Hi, I have been having numbness in my right hand and arm. This happens mostly at night while sleeping. However it does sometime happen during the day. This morning after having a tough time sleeping last night due to this problem, I have red rash under the skin on my right hand and arm. The rash does not itch. Looks bad though, do you have any suggestions?