Stormlight healing works with how someone veiws themselves, which sometimes goes against the reality of their situation. Kaladin's scars won't heal because he still views himself as a captive, but this took over a year of surviving some of the most brutal conditions possible while dealing with some serious depression. I'm not sure where Rysn's interlude on the Reishi Isles falls in the timeline, but I don't think that being a useless cripple will become part of her core identity in a hurry. Especially with her adventurous attitude, if she gains stormlight the first thing she will want to do is go explore her new powers.
As a sidenote, her and the Larkin might get to spend some quality time with the pot of grass. Might make for some interesting conversations.