I'm due to donate again next week. I find the process a little uncomfortable these days. The 'slight scratch' (why do they say that? It's not like a scratch at all. It's much more like a needle being stuck into your arm, which isn't - to my mind - something that requires a simile, much less an inaccurate one) is now a painful* jab, which remains painful throughout the donation, including the removal and shortly thereafter.
One member of staff told me that this is likely due to scar tissue. Another (different occasion) suggested a duff (cheap) batch of needles.
Whatever it is, I'm going to ask them to use the other arm next time, to see if that improves things.
(*FSVO pain. It's more painful than it used to be, but still only, say, 1.5 where renal colic = 10)