sorry no one has responded to you yet. but like me, probably no one else has experienced anything quite like this. i do have a friend with an htc hero who has had to have her phone replaced several times because she developed "dead" spots in the screen. she is a big texter and i guess just wore out a few places on the screen. wish i had something useful to offer you, but in this case i don't.
Yeah, I've never heard of this either. I'd recommend taking in to Verizon and asking for a replacement. If you're still within warranty, that won't be a problem. If you're not, they might not be willing. If Verizon won't replace it, you can get replacement screens from ebay for $30-40. You can do the job yourself easily, and it's a lot cheaper than buying a whole new phone.