I tried to host a server, which required me to create an account here and link it to steam. My helmod settings are gone after the name change. I did the characters name swap, which got me back my inventory, hotbars, etc, but Helmod is wiped. Everything else seems fine, including settings in other mods (Note there were a few interim things that happened... i didn't like the new name and changed it, for an example. Not sure if that's relevant).

Is there any way to get it back?

Ah no, a good portion of Helmod's settings are stored with the username, and there's no way to reassign anything to the new name.
An option to be added in a future update