What methods [however silly or absurd they might seem] are effective in bringing oxygenated blood to the skins

Mage is an excellent way because it stimulates the circulation in general and particularly the parts of the body maged including the skin. This brings fresh, oxygenated blood to that area and helps with all sorts of conditions. I suppose the answer to this question really needs a specific reason as to why you need to do this, as there maybe other things that would help too and possibly contra indications. Deep breathing is obviously excellent and cutting out anything that leaves you oxygen deficient, like smoking if you do.