Hello and welcome to e health forum.
Please note that you are still very young (22 years) and it is too early for you to worry about your breast size.
Once you grow older and as you conceive, your breasts will enlarge and attain their normal size.
Your doctor, has prescribed Diane 35, to treat your cysts in the ovary, which might be the cause of your irregular menstrual cycles.
The pills contain estradiol ( a estrogen like hormone) which increases the breast gland formation and hence the breast enlargement. Regular use of Oral hormonal pills (like Diane 35) will definitely help to temporarily increase the size of your breast and it subsides once you stop taking the medication.