First off, consider your direction, parasites???? on a monitor that was just hatched? then consider its parents were captive hatched and so on and so forth for many many generations. This line of thought is most likely of no use.
Also I whole heartedly recomend you slow down of the worry thing. Worry does absolutely no good other then cause you problems. It will not help the monitor.
You cannot worry about every little thing.
On to your problem. You must understand, that a cage, its conditions, and the actions of the monitor are all related. Its very possible that your monitor has reached the limits of the cage and its conditions. That is, your conditions only allow so much to be digested. If they cannot digest in a normal sequence, they regurg. Its not the monitor, under its own choice of conditions, they can eat huge quanities and very very large prey items. In your cage, they do not have a full choice.
Also consider, you do not to give them a full choice, you may consider balancing it out. Like feeding less food at a time and feed more often. Or just feed it less and it will grow slower but will not regurig. You can feed to the limitations of your cage. If you understand this, then you understand, its not only the monitors ability, or the cage conditions, but also your input as well.
What I have hoped to teach you is, you cannot set up a cage, put a monitor in, and let it make music. I do not care what set up you have, you have to control both the monitor and the cage. You must "monitor" the progress and make adjustments. You are "the" keeper. You have to adjust to replace what the monitor would do on its own.
Consider, in nature if a monitor needs change, it changes. If it needs different temps, it gets them. If it needs to rest, it rests.
Which brings up my last thought. Sometimes you should allow you monitor to empty its stomach, They do not need to eat every single day. A rest here and there is not going to harm them and may be of benefit.
The above is considering your cage conditions are fine and not too wet, too hot, too dry, too cold or any combination of these. Cheers
