HTC Desire : Getting A Tingling Sensation In My Finger

I've had a screen protector on my HTC Desire since I got it (brilliant phone!). Two black vertical lines started to appear on the screen (only really visible when the background screen was white). So, I decided to take off the screen protector and risk scratching the screen.

However, without the screen protector, when I moved my finger on the screen I started getting a tingling sensation in my finger (a bit like that sensation when there's static around). I tried it for a few days and it's still the same. Has anyone else had this?

(This is the first capacitive touch screen I've had- I've only had Symbian UIQ touch phones in the past. I'm going back to having a screen protector which although not as smooth as the screen is at least comfortable to touch!)