So ive never had any problems with using tweak until i downloaded the latest patch for the westhill track and now everytime i try to use tweak lfs crashes. So my question is how do i fix this or is There any way to delete this patch?

Don't come here asking for help on any unsupported modifications. If Tweak or any other unsupported mod crashes or breaks your game contact the modification developers for help.

Ok but can you answer my other question instead how do I uninstall this patch?

You can't "uninstall" this patch.. Files are overwritten. Only thing you can do is install an older version of LFS.