You "open" a RAW file in Lightroom when you imported the picture in the catalog. When you now work on your picture all settings are stored in the catalog. The RAW file wouldn't be changed. The settinge were applied to the picture when you exported the picture, ex as a jpeg.
LR doesn't specifically OPEN files. You first have to import the image file into the LR catalog, a database file. Once that is done then you use the Develop module to make edits on the image. These edits do not change the original file in any way. LR stores the edits in the LR catalog file, and an XMP file if you have that option checked, and Displays the edits on the image, lays the edits on top of the image, when viewed.
So you can go back to the original image file, whatever type of image file you started with, RAW, JPG or whatever, any time you like, a day, month or years later, and continue editing or remove all edits.
The original file is not touched.
The only time the edits get Burned Into an image file is when you export it and a new file is created.
Specifically, I'd like to just continue editing what I have, meaning that all the previous adjustments haven't been finalized but are still changeable in lightroom.
Find the photo in the Library Module, select it, click on the word Develop (or press D), and then continue editing the photo in LR