A pic of the foot would help. I have seen several bunnies with sore hocks that didn't act strange at all, and for some of them they were actual scabs on the heel. However, all of these guys had both feet sore, so they couldn't really get away from walking on it. One was in a shelter situation, and I was the only volunteer who noticed it, and I only noticed the sore hocks because I was trimming toenails and cleaning scent glands one day and saw them.
With my bf's little nethies (Frida and Benjamin), they sometimes get sore hocks due to standing on dirty litter and poo (he cleans the litterbox once a week, doesn't have a grate over the poo, I'm not too happy about it but all I can do is try to make him feel bad about them getting sore hocks so that he is better about changing it).
There was a week that I was very sick and didn't change the litterboxes, and one of my guys got sore hocks for the same reason (Tony, a dutch). The lop (with extra-fluffy lop feet) didn't get sore hocks. I had one litterbox without a screen (they all have screens now) and that one got pretty gross and messed his feet up.
In all of these situations, I never noticed them walking funny. The heels of their feet were hairless and red, with some dry, dandruffy skin scales and I think one of the nethies had an actual scab at one point.
Bunnies will usually run away if you touch any part of their feet.
I would recommend trying some craft plastic squares to put over the litter. These allow the pee to run through on to the litter, so their feet don't have to come in contact with wet litter. It also should keep her from eating the litter. If the plastic bugs her feet due to the hock, they won't work well. I got mine in the craft section of wal-mart. It is frequently called "plastic canvas"
http://www.hobbycosf.com/plcash7co10.html
If the plastic grids work and don't bother her feet, or if applying the bag balm makes the sore hock go away, she should stop limping. If it's not just a sore hock causing her to limp, these things won't make the limp go away.