A DNG file is a raw file, Adobe just recoded your original into their format. As such you lose no information when converting it later to e.g. a tiff or jpeg file. If you really want to, you can actually also embed the original raw file into the raw file, that way you could keep one file and still have the ability to revert back to the original raw file if you'd ever wanted to. People who have completely adopted a DNG workflow usually don't bother with this though; it dramatically adds to the file size (and from their perspective for no gain at all).
If you were to switch to e.g. Nikon Capture NX2 for your raw editing, your edits will be visible in PM, without having to do anything; Capture updates the embedded jpg when saving files. I actually love this feature as the embedded jpg is actually of a very high quality, allowing you to use it for almost everything (even printing). PM's ability to use these embedded jpgs comes in mighty handy here :-)
Hope this helps you make a decision for your workflow,
Hayo