I have an old hematoma around the glans of my penis. applied arnica and heparin to no avail. is it possible to drain it or would that damage nerves?

Self-treatment: These two meds applied by someone without special equipment won't touch the lesion in question, whatever it actually is. Don't incise the lesion on its own even if seems fluid-filled -- this is something you do not want have get infected. If this bothers you or the lesion really interferes with function, you need to get with a competent urologist.