I have LI and I get that all the time, too. I don't get those comments as much as I used to, though, since I started wearing foundation & makeup--that covers up most of the redness.
Most of the time, I say (nicely) I'm not sunburned, I was born this way, the same thing goes for my hands. Most people just leave it alone then. No more questions and no more comments.
Sometimes I don't feel like getting into my medical history w/ strangers, so I just smile & agree with them, saying something like "I was on my motorcycle all weekend" or something like that.
If the grass looks greener on the other side, maybe it's time to start watering your lawn!