Newest slang use of freaked out, scared, upset by something whether disconcerning or not. Used mostly by older people with an attempt to connect with the younger generation. Usually not successful.
A sunburn or suntan focused on the left arm. It is caused by the left side of the body being the only half that gets exposed to sunlight while driving. Presumably, it would be located on the right side of the body in countries where they drive on the left side of the road.