First of all, don't be so hard on yourself. None of us is perfect. Remember that. Go, have fun, and stop worrying so much about your imperfections.
As far as what to wear, you can find some very thin fabrics that camouflage while still letting your skin breathe. Also, maxi skirts are a great option! Very comfortable and easy to wear. If you get the right kind, they are great to pack since you don't have to worry about wrinkling, since they already have the wrinkly fabric.