Impaction is defiantly a possibility. I suggest giving him regular warm baths (at least once per day). Don’t have the water too high, he must be able to touch the bottom without issue and have the water warm but not too hot. Don't let the water go cool, as this will exacerbate the problem.
Try to encourage him to drink if he doesn't seem to much on his own - you may have to add droplets to his snout for him to lap. Hydration and warmth is key here. He must have access to clean (conditioned) water every day. I agree with the substrate of damp paper if he's still quite young, and since he's having problems it's best to take him off sand to avoid further possible ingestion.
It's absolutely necessary not to feed him anything too large - your woodies must be smaller than the width of his head but smaller is better - they will just eat more and digest them a lot easier. Make sure to calcium dust every feed - very important for a growing dragon.
He will need a UV on for approx. 14 hours per day and it needs to be 8 - 10% depending on the brand. They have very high UV requirements (at every age) and he will not be able to metabolise the calcium you give him without the UV to produce Vitamin D3.
I disagree with the 50˚ basking recommendation. 45˚ is the absolute max and it has been proven in scientific studies that at 46+˚ these dragons can lose coordination and the ability to move when necessary - 50˚ is considered verging on expiration for these guys. Plus it forces them to continually move back and forth to regulate their temp.
Another thing is substrate heat - these guys spend a lot of time on their bellies on the ground and that means they need warmth their too. Not too hot as it can cause constipation (and thermal burns in extreme cases). A heat mat or cord applied preferably to the outside underneath the tank attached to a thermostat and set at about 25-30˚. Make sure to feel it with you hand and gauge it since extra overhead heat could make it too hot if your thermostat is set high and it will struggle to regulate it. It doesn’t need to be really hot just not cool.
Apart from that if you are really concerned and don't see any progress then take him to a reptile specialist before it's too late.
Hope he gets better!