It's a long process to heal, there is no instant fix. Since SLM have a 10-14 day life cycle, even if you kill them, the eggs will hatch and they'll come back. I tried all the vaseline/soaking/AD ointment but it's very messy and I didn't see any results after about 3 weeks so I applied 5 drops of pour-on ivermectin (for cattle) once, and again 14 days later. I started seeing results in about a week, but it is a slow process.
The deformed scales don't come off until a new healthy scale grows underneath. I've read about some chickens taking up to a year to fully heal. Attached is a picture with healthy new scales highlighted.
This picture is about 2 months after first dose of ivermectin, but this is also a pretty severe case of SLM.
Also, like others mentioned you should probably trim her nails. Those long nails mean her toes are going to be bending back, which will put pressure on the deformed scales.