First things first. Sterility. Only use new pins and do not share, do not let the pins make contact with anything that may be hazardous by keeping the plastic covering on when not being used, use substances which you are sure are legit, reputable, and are sterile, wash hands thoroughly before any procedures, inject in a clean sterile environment, and make sure the injection site is cleaned with antibacterial agents before and after administration. It’s easy to just skip this paragraph or become lazy over time, thinking that you will be fine. If you want to reduce your risk of infections (which can be very painful and put you out of training for a while), then always think about sterility before and after administration. Be smart.
Noxious input to the spinal cord is known to produce central sensitization, which consists of allodynia , exaggeration of pain, and punctuate hyperalgesia , extreme sensitivity to pain. Two types of mechanical hyperalgesia can occur: 1) touch that is normally painless in the uninjured surroundings of a cut or tear can trigger painful sensations (touch-evoked hyperalgesia), and 2) a slightly painful pin prick stimulation is perceived as more painful around a focused area of inflammation (punctuate hyperalgesia). Touch-evoked hyperalgesia requires continuous firing of primary afferent nociceptors, and punctuate hyperalgesia does not require continuous firing which means it can persist for hours after a trauma and can be stronger than normally experienced. In addition, it was found that patients with neuropathic pain, histamine ionophoresis resulted in a sensation of burning pain rather than itch, which would be induced in normal healthy patients. This shows that there is spinal hypersensitivity to C-fiber input in chronic pain.