I only tryed it once after cutting my thumb with a razor (1cm long deep cut) and it did sting, with my 200mW green, but I saw the blood harden black instantly, and it sealed the cut. I couldn't push down and break it, was sealed. Usually cuts remain open for weeks. This one didn't
Trying to cauterize a cut with a green laser is probably not a good idea. Imagine how a normal green laser feels on the back of your hand, then multiply that by 100 times. That's how much it hurts. Blood absorbs the green light a lot better than skin does.
Also, you would either need to focus the dot a bigger to cover more area, or just stick to sealing up the paper cuts.
I don't mean to be an ass again, but I am calling BS on your post jbtm. I have tried and have also sat through the pain, and it does not work anything like what you have described. The blood does not turn black and the cut is not any more sealed than a normal scab. All a green laser will do is harden the blood faster, it will not "melt" your skin back together.
Wickedlasers used to have a chart that showed what powers do what, and there was a section for cauterizing blood. This has been discussed quite a bit because of that....