Light from a red laser. Credit: Wisky [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0) from Wikimedia Commons].
Read about the use of red lasers to treat neuropathic pain:
N. R. Gough, Zapping Chronic Pain with Red Light. BioSerendipity (26 April 2018). https://www.bioserendipity.com/zapping-chronic-pain-with-red-light/