It depends. It won't go away on its own and it depends firstly, on how bad you are at diagnosis and secondly, how motivated you are with diet and exercise.
The problem is that there will be some damage to the insulin producing beta cells and no one ever knows how much damage there is. It used to be thought that these were either dead or alive and, once dead, there would be no recovery. However, it now appears that some are not actually dead but blocked and, if they can be unblocked, they will start working again. But, some are definitely dead and so you will always have to be careful. On the other hand, that's not too bad because if you went back to your earlier diet, you'd be going back to one that gave you the diabetes in the first place.
The advice given by the NHS has been to keep your after meal readings below 8.5 and your early morning readings to about 7.0. However, these are far too high and the Belfast Study showed a few decades ago that, whilst this looks as it the diabetes is well controlled, those high levels will lead to more beta cells dying and the condition getting gradually worse.
The first thing to do is find a diet that works for you and helps you get your blood sugar levels down to below 6.0 in a morning and below 7.8 two hours after a meal. Eating fewer carbs and eating only carbs that are low GI will help greatly in this. The next thing to do is lose weight as this helps unblock your blocked islets. Very roughly, your body needs about 220 g of glucose per day and, if you eat say, 100 g of glucose, it will extract the extra by producing it from stores of things like fatty acids. A lot of these are depositied in your liver and pancreas and, if you lose enough weight, you lose a lot of the fatty stuff there.
Exercise is a big help. Not so much the pumping iron, get your heart fit type things but regular daily exercise. This actually alters the blood chemistry. Hormones are released which trigger the production of certain enzymes which then digest your food in a different way. You are not burning off the pounds but you are altering the way your body deals with the food you eat. You can of course still do more exercise but, walking off a meal and taking a daily constitutional is a big step forward. Another thing about daily exercise is that it improves your insulin sensitivity so you make better use of what insulin you are producing. It becomes more efficient. This, in turn, helps lower your BG levels.
Many people here report getting their blood sugar levels to well within normal ranges. Many of us can get away with eating stuff we shouldn't eat. But we better not do that too often, or it will come back to haunt us.
I enjoy my food but I cook most of it myself. No ready meals or ready made sauces. Everything cooked from fresh ingredients, careful with the carbs and avoid the sugar. White bread is probably the biggest stumbling block for most type 2s. If you eat modern white bread, you may as well be eating sugar. I stick to brown rice, wholewheat pasta, rye bread and things like that. And, I am careful about the quantities. I try to keep things varied so I have two red meat days per week, two poultry days, usually one duck and one chicken, two fish days per week and one vegetarian day.. It is so much better than sticking a frozen pizza in the oven.