If they are visible in the hoard, then they are not hamster mites, so won't get onto the hamster, they will be some kind of bug that has hatched out from the food. We usually recommend freezing all hamster food for a week before using it as that kills bug eggs! Unfortunately nearly all pet food contains moth eggs and bug eggs and they're not visible to the naked eye - they hatch out when it gets warm - either in summer or in winter when the heating is on.
If you freeze the food first you won't have that problem.
What you need to do now is a cage clean. If they are just in the hoard and nowhere else in the cage, you could just clean out that end of the cage and that might be enough. Unfortunately it does mean throwing away all his hoard and nest and putting all new bedding in that area. I'd also wipe the bottom and side of the enclosure at that end with a warm cloth as well. To wipe anything off that might be there. Then all new bedding at that end.
See if that solves it. Hopefully they'll be gone. If you still find them in a couple of weeks then you'll need to do a full cage clean and disinfect all the contents as well - but if they've just hatched out of the food, you should be ok just doing that one end.
Alternatively you could just do a full cage clean now, wipe down any cage contents and hope that does the trick without needing to disinfect the cage contents.
Do you have a photo of your cage set up? I might be able to advise more on what to clean and what can be left then
It could be this that is making him bar chew as well, if it's bothering him.