I had an epi. It's a strange sensation. I could still feel sensations like pulling when DD was coming out (but when it's time to start pushing they make you stop self administering so you can feel it a bit). I could move my legs and feel when they were itchy but they felt like dead weight.
Straight after DD was born and they took her to neo-nates and after I had been stitched up I wanted a shower and was told that I could only have a shower if I could walk to it which I slowly managed to do with DH's help. My legs felt like jelly for about an hour or two after I started moving around but I could move. I got DH to stay in the room with me while I had a shower just in case I fell though. I had to lean on him while I got dressed.

I don't remember having a sore back.

I took about 12 weeks to recover from giving birth but I think that was due to a difficult birth, not due to the epi.

The only thing that I was worried about was I remembered at one stage that I had a cathida coz I couldln't feel sensations enought to know when I had to pee during the epi, but the cathida was not inside when I was having a ven tous. At some point I had pushed it out which worried me a little because there is a little balloon on the end to keep it in.