so, if you are fishing a tube and lose the tube, do you have to completely retie??

Depends on how long since the last retie. If you lost just the tube on the third or fourth cast, just put another on and keep fishing.

but how do you get the line and eye of the hook in the tube without retiing

If that's your rigging, retie.

Texas Rig it

There are a lot of variations of this on the market. If you do not want to re-tie and go Tex-posed these work well. Lot of videos out there too. People have come up with some creative ways to rig tubes.

Back when I fished tubes a lot, I used the Shaw Grigsby HP hooks (the ones with the keeper).

Depends on how I'm fishing the tube...

texas rig - I check my line often and re-tie as needed. If the tube gets pulled off, I replace and move on.

Stupid tube - I usually cut it off, re-thread new tube, then re-tie

Always re-tie if in doubt.