hello and welcome to HCM,
In the era of modern safe medicine and safer and less harmful antibiotics I am surprised and pained that you have to take penicillin and that too four times a day! And you are wondering why you have so much of ulcer!
If your infection is controlled please stop all antibiotics and pain killers as they will only make the matters worse.
Take only bland non oily, non spicy food with lots of green leafy vegetables
Add a good vitamin tablet with lactobacillus
spores for regenerating your good bacteria in the body
Start anti reflux medications immediately in consultation with your ENT and have a proper diet in regular interval
take care and get well soon
Do not worry, our body has amazing capability to recover, just give some time.
Meanwhile you have forgotten to mention why the doctor gave you penicillin in the first place
take care and get back to me if possible
Dr Sriram Nathan