Paintball is just one of those games that you need to prepare for, if you dont prepare chances are your going to get hurt more than you should, I strongly suggest to never have exposed skin if you can help it.
Now I dont mean that you need to bundle up in body armor or anything, but one or two layers of light clothing, like t-shirts with long sleeves and jeans instead of shorts, can easily protect your skin from unecessary damage, it wont prevent you from getting hurt, but you have a much better chance of not having your skin broken. I've been hit all over and I have never bled a drop, not once, because I allways make sure all my skin is covered. I use a basic light paintball vest, neck protector, an old pair of Lacross thigh padding, and a simple camo jumpsuit. The jumpsuit absorbs a lot of the force and the light padding absorbs what extra energy is left.
But as for the worst place to be hit, I wouldn't say the groin, I would say the neck is the worst place to be hit. (Besides your eyes and face, which shouldn't have been hit anyway if your following the rules.) My dad was hit once in the neck, it was pretty bad, his neck was exposed and he took a hit right under and to the left of the adams apple. He bled for a while and it swelled up pretty bad and he had a hard time breathing and eating for the rest of the day. The frist thing I did after that was go out and get myself a neck protector, and I'm really glad I learned that lesson early on.
Like I said, painball is a game where you need to prepare, wear proper clothing, dont bring super expensive cameras unless you can protect them, amke sure you have enough paint and Co2 for multiple games.
If you prepare, paintball can be a really fun game to play.
