Faster and faster

I'm trying to play the J.J. Quantz Presto (of Arioso and Presto) up to speed, which is quarter note=108.  That's extremely fast, and perhaps faster than I'm able to play.  The sixteenth note runs, that is.  After some weeks of taking it at a tempo that felt comfortable, I'm now pressing ahead with the speed, which is very difficult for me.  I can't play with the metronome going--I get too flustered when I can't keep up--but listen to it before I start to try to set the pace as close to that as I can get.  I lose focus and get distracted easily, and now the words melanoma and cancer run through my head a lot.  And I look at all the spots on my skin--I have so many.  I used to worry about them turning into age spots; now I wonder if they're going to develop into melanoma.  I read that the most common place for melanoma is women is on the leg (for men it's on the back).  I see a large splotch on my left leg, along the shinbone, and it seems to turn ominous before my eyes.  And my hands--I have red splotches; will they start to turn malignant?  Do I just watch spots and splotches turn into cancer, or is there a way to arrest their possible development?  Is whatever is currently on my skin already programmed to whatever it will become, or can I influence the future now that I know that melanoma in situ is a precursor for invasive melanoma?  Is the Trojan Horse already in place?