This study seeks to determine if photobiomodulation (PBM, or low level laser light) affects the growth and distribution of nerves int he skin. Our previous study demonstrated that the treatment we use here was effective at reducing the symptoms of neuropathy (as measured by the modified total neuropathy score) in patients who had been treated with chemotherapy. The current effort is designed to repeat this confirm this observation using a more extensive battery of survey as well as to begin to elucidate the mechanism through which photobiomodulaiton produces the effect. WE will also be attempting to determine if diabetic patients differ in terms of response from chemotherapy patients

Consenting patients with self-reported neuropathy following either diabetes or administration of chemotherapy, will undergo sensory testing and skin biopsies of the the foot and leg prior to initiating treatment. They will undergo PBM 3 times weekly for 6 weeks with with a follow-up biopsy performed at the conclusion of therapy and sensory testing throughout. Patients will have one remote evaluation at 26 weeks to determine whether the effect, if any extinguishes.

Inclusion Criteria: self reported neuropathy following exposure to diabetes or chemotherapy

• willingness to undergo biopsies and 6 weeks of therapy

Exclusion Criteria:

• pregnancy
• active cancer treatment