Hi I Have Rash On My Lower Right Arm. It's

Hi I have rash on my lower right arm. It's all raised bumps. It's really itchy. Benadryl doesn't help. I got a tattoo on my wrist on that arm on April first so about two months ago. I don't know if I'm rejecting the tattoo or something but it's spreading. It started contained to my wrist area and now is from elbow to wrist but only on the inner part of my arm. It also reaches around and is on the top part of my hand where there's no hair. I'm an 18yo girl if that helps.