Summarize:

Many collapsed veins cannot heal. Permanent damage can also occur in a very short amount of time. If you believe you have a collapsed vein, contact a doctor or clinic to discuss treatment options. In order to give a vein its best chance to heal, stop injecting into that vein altogether. Vitamin C and other supplements may help fight inflammation within the veins. That said, no supplement will eliminate the risk of a collapsed vein, nor guarantee that a collapsed vein will fully heal. It's always best to see a medical professional immediately if you believe you may have a collapsed vein. If you are diagnosed with a recently collapsed vein, a doctor may prescribe blood thinners that will help thin your blood and encourage it to circulate. In other cases, they may recommend surgery to repair damaged veins as much as possible.
Recognize the severity of a collapsed vein. Ask a medical professional about supplements that may help. Anticipate medication or surgery.