Unfortunately, you harbour a condition referred to as NEUROFIBROMATOSIS.
I very much wish there were a definitive cure for your problem by using medication but there are none of the types you seek in order to reverse the presence of the neurofibromas in the left forearm and back.
Sometimes if the neurofibromas become so large that they cause unrelenting or excruciating pain on a structure in its vicinity then, surgery can be done to remove the fibroma.
The problem, however, is that they tend to come back after time and secondly.
Sometimes the lesion is so enveloped around or within a nerve
or group of the nerve that surgically removing is not easy or even recommended.
Since the nerve itself would have to be sacrificed and this has other consequences compared to pain or other feelings of neuropathy.
Hope I have answered your query. Let me know if I can assist you further.
Dr Dariush Saghafi, Neurologist