Overgreasing the front part of the rear drive shaft?

I was greasing my driveshaft today on my 03 4x4 and started with the section in front of the support bearing towards the front of the truck. It looked very dry. I started pumping the slip joint with grease expecting it to come out of the joint but 20 pumps later I could sort of see the shaft pulsing (extending) and still no grease came out.

After reading I learned that this is important to not overgrease and it only takes 5 pumps from time to time. So that's what I did on the rear slip joint near the diff.

To me it doesn't look like there's a lot of movement in the front shaft during suspension movement, more like movement in the bushings.

Two questions:
-do I need to worry or do anything to release the pressure or remove the grease?
-where does the grease physically go? Was I just filling up the hollow tube with grease? Could I risk damaging some seal in there?

Thank you

 

My bad - upon a closer look it was the small drive shaft going from the transfer case forward to the front diff that I pumped up