ok guys if a deer comes in a say 10 yards do i just shoot hime with my 20 yard red dot should i aim low or ?

At 10 yards, assuming a 100 yard zero, aim at your desired point of impact.
Your bullet will be rising, but it's close enough that it won't make much of a difference...depending on your caliber.

yep anything under 20 i usually aim with my 20 yard spot on my scope.

Look at a ballistic calculator. Assuming you are sighted in at 20 yards, at 10 yards with an arrow traveling approx 300 fps, your 20 yards pin (or crosshair) will hit about 1 inch high.

My Parker Scope has multiple cross hairs.
The main mark is 20 yards and use each lower on for another ten yards.
There is one above the main cross hair for a 10 yard shot.

Not sure of your bow type or arrow speed, but I shoot an Excalibur Phoenix with a Leupold scope (duplex reticule - single crosshair) on it.
I sight in for 25 yards and the arrow is under +/- 3" in trajectory from 0 - 30 yards. A center of the "kill zone" hold will (and has) kill any deer shot with it this way!

All I need to do is make sure the deer is inside my 30 yard zone and it's dead if it offers a good shot angle.

how about you trying a 10 yard shot at a target so you know for sure instead of asking people who have no idea ??????????