It goes away in that your blood pressure readings will be normal if you control it properly.
And you are very right, losing weight, controlling the salt and a lot of the other things you'll be doing as you get going on healthier, fitter lifestyle will help you to control it. BUT . . . like a lot of other conditions, it doesn't go away to the point that you can revert to your old diet and exercise routines. Of course, you won't do that because those are the same things that will also bring back the weight.
BTW . . . once you get the salt under control, you'll find you don't miss it. A lot of stuff (canned soup for example) taste so salty to me, I hardly ever eat anything but homemade anymore. However, just like it is hard to switch to lower fat milk, and to give up sugar in your coffee; it takes time to kick the salt habit too.
Just keep on taking baby steps. Do the very best you can as much as you can and the rewards will come. Remember nobody is perfect every minute of every day.
Have a great moving and shaking evening, chickie.