Scars on top of Another

[blueyedevil]

I had a scar on my hand that wasn't going away, not long ago I cut myself and part of the cut was over the old scar. Now looking at it, the old scar is gone...can anyone explain this to me because it doesn't really make sense. Will the old scar come back once the cut has healed? (do you reckon)

[Calvesy]

When you suffer cellular damage in tissue injuries, a hormone called histamine leaks out and as well as causing increased bloodflow and pain to the region it also stimulates cell division at an increased rate to replace damaged neighbours.

This would be a cancer unless the rapid cell division is stopped after a genetically predetermined amount of time, so it varies from person to person how well injuries heal. A molecule called a telomere at the end of each chromosome is slightly shortened by each cell division. The cell dies after a certain number of divisions are made, putting an upper limit in human lifespan to about 120 years if you do not succumb to disease, injury or cancer before then. There is an evolutionary tight rope walk between gaping festering wounds and runaway cancer, so in your case in seems that the incomplete repair that manifested as a scar was jump-started back into action by a further injury to the same area. Watch your skin over the summer as it tans and fades to see how closely the scars are able to blend in with the rest of your hand.