My dog was extremely filthy from head to toe, so I left him.
What are you trying to do by leaving your dog?
I was getting rid of an obstacle in my way to being less burdened for another being.
Leaving your dog is irresponsible, as is not taking him to the vet. Get your dog the medical care that it needs.
I was giving him a chance to survive.
You're doing the opposite, this is not helping your dog survive. It is your responsibility to take care of your dog and manage its hygiene. I would recommend going back to your dog and dropping it off at a shelter so it could be cared for.