Q: Damage to rear Differential? 1994 Chevrolet K2500

I have a full floating rear axle under my 2500 Chevy. Not HD. My truck was worked on by an incompetent idiot who claimed he was a "mechanic" and now i'm a little concerned. My bearings in my axle shaft are oil lubed from the Diff. When the idiot worked on my brakes, he packed my inner bearing just behind the wheel seal, with Red and Tacky grease. What kind of issue can this cause, both in my axle housing and my differential? Do i need to yank that bearing and clean it out/change it, then flush my differential, or will it be OK. There is another bearing past that one, that i am a bit worried may not be getting oil if the red and tacky grease is stopping it. I've always been told never to mix grease and oil, especially in rear ends. And i know red and tacky is more of a cheap grease. What do i need to do to protect my truck and prevent any damage, if i have not caused some already? The bearing was packed about 3 weeks ago. I just found out about it today. >:/

My car has 250000 miles.
My car has an automatic transmission.