I had read that you can use a laser pen/pointer on canker sores. I tried it, but the beam was so narrow it was hard to do larger sores. I had purchased the TenDlite for aches and pains, but tried it on my canker sores. It works perfectly. I had one starting under my tongue and the light completely got rid of it within 3 days. I used it maybe 3 times over a couple of days (1 minute sessions), then left it alone...gone, no pain.