+1 to willow
I have worked in the nhs, and do kind of now (I'm a student atm). I work with patients, and so have to be bare below the elbows. I've found people to be supportive too despite having obvious scarring which has on occasion (after a crisis) been recent. A few (minimal number really) ask....most of whom really are truly blissfully oblivious, and remain so! If you are *wanting* to go the lab route you should be fine. However I would say please, please don't let scars stop you from doing something you want to do. I almost let the fear of having to show my arms stop me......but I am sooooo glad I didn't.....I love my job so it was worth the battle.