By the way, you may want to start taking DGL before you eat. It's licorice, without the stuff that causes higher blood pressure in licorice. They usually come in chewable capsules, and help build up the protection of the stomach wall lining. Additionally, aloe vera juice may help.
I noticed you did this in reply to a thread about gastriparesis. Have you been concerned about that? Have you had a gastric emptying exam done? (Both heartburn and bloating are gastroparesis symptoms, but they could just be dyspepsia.)
It all depends on the severity of the situation and how well the medication is working, in addition to your diet. If you make sure to avoid any acidic foods (citrus & berry juices and fruits, garlic, coffee, carbonated drinks), as well as taking your medication as directed, you may be looking at at 6 week recovery time. Of course, only your doctor can determine whether this is sufficient.
Was there any reason given for the gastritis?