I have a large red lump on my lower arm that appeared when I woke up this morning. It is very swollen and hard to touch, closer to a bug bite than a lump. the swollen outside is light pink with a darker pink center. It is not itchy, but it very painful to the touch. I initially thought it was a pimple or ingrown hair , but it has not raised to a head or anything. Could this be nasty spider bite? Something else? Should I be worried enough to go to a doctor? I don`t have insurance and would like to avoid that if I can.