La terapia dé la luz roja, although still not medically proven effective, is understood to help considerably with healing surface issues in the face, mouth, tongue, and throat. These lights are available in many on-line shops as well as some pharmacies. The trick as I understand it is to have the proper wavelength of red light. Some units are simply a general red color rather than a specific wavelength close to infrared light.
Many patients here believe it helps considerably with pain and healing. Perhaps that is the importance. If it works for you, then it helps.

@jubilta77, I moved your question to this related discussion where you can connect with others talking about red light therapy.
- Anyone have success with red light therapy for radiation effects? https://connect.mayoclinic.org/discussion/red-light-therapy-success/