What's messed up exactly? The web gallery (i.e. html and JPEG files) that you exported? The web gallery collection in Lightroom?
Or did you try to build your own web gallery using the SDK?
Tell us what you did to get to this point?
When I entered the WEB module in LR, the old messy unsaved web gallery I had tried to create (my first try at one...) would always reload and pop up, blocking any possible other work on a better webgallery for me. I wanted to start over ... but could do nothing really ... Never got to export anything as i did not want to do export my garbage ...
I finally did understand an earlier comment on another query (similar topic) that suggested one go to the Adobe folder in Applications and delete the subfolder on "web galleries".
This miraculously worked even as my 'unsaved' web gallery never showed up in my Applications/Adobe/webgalleries, not even after re-starts of LR. Miracles happen.
Another work-around I discovered is to make such busted unsaved web galleries "saved" and then delete them inside the Library module of LR where they now appear and can be killed, finally.
Ps: what is SDK?
SDK is software development kit - the thing you'd likely have been playing with if you'd been building your own web gallery templates (which is what the Applications/Adobe/webgalleries folder was referring to.)