One of the first concerns I have when replying to this post is that your husbandry might not be well enough for this reply.
If a monitor is in proper care a wound like this will heal quite well on its own.
So, if you would like a good reply, please post about your husbandry then if your husbandry is good we will tell you, don't worry about it. If it is not, we will help you correct it and might forward you to a vet.
This girl here came in like this, she also had a large scar on her head and was bleeding pretty good. I simply used triple anitibiotic on it for a few weeks and intermittently washed it and bandaged it. She fully healed and within a month and a half laid a nice clutch.
thanks,andrew

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VARANUS CREATIONS
Breeders and Hobbyists of Kimberly Rock Monitors, Red Ackies, Argus, Argus x Flavi crosses, Gouldi x Flavi crosses, Argus x Gouldi x Flavi crosses, Jungle Carpet Pythons, Bredl's Pythons, Dunn's Pythons, Western Hognose Snakes, South American Boas, Atheris Squamiger, Leopard Geckos and rare Spiders.