What Can Help With Tingling Sensation, Numbness, And Tightness In Chest While Attempting To Withdraw From Heroin?

I've been injecting heroin intravenously for a while now. A few days ago I did a little over half a gram of black tar in different shots and the day after my left arm felt a little weird. I am familiar with the sensations that come with missing a shot, but I have never felt anything like this in my life before. A single long vein in my left arm feels like ice cold water is running through in when I stretch my arm out and twist my wrist. Icy cold sensation is the closest I can get to describing it, or some may explain it as a tingling sensation, numbness or tightness. Tightness is a good description too. It doesn't hurt, although it really worries me. I have injected this vein many times before but not where I feel this col sensation. When I look at my arm in the light, it looks like the vein has literally collapsed in one area, which is where the sensation begins. The collapsed part of the vein in only half an inch long, with barely any discoloration. I am afraid that the sensation is spreading to the same area on my opposite arm in less intensity. The rest of my body is fine. This is my second day into withdrawals, and I might just be freaking out but this is definitely not normal. I can neither go to an ER or see a doctor right now.