Good work healing your severed pinky with skinwort. I’m afraid I have no explanation for why the rest of your arm started growing fingers.
There’s one account in LOST CURES, REFOUND AND REIMAGINED (very entertaining book; I’ll loan it to you) of a German man who died in 1911 after drinking skinwort tea. The following spring, a “flesh tree” sprouted from his grave.
I’ll keep researching possible causes of your finger problem so we can all avoid similar trouble in the future.
The best option I can suggest is to chop the extra fingers at the root and heal those spots with more carefully applied skinwort. I recommend a jigger of St. Madelia’s spirits before you get started. It’ll dim the pain without making you groggy.
I wish you lived closer so I could help in person, Amanda. Please let me know how it goes.