There is a lack of medical evidence that what you eat affects acne. Acne is caused by high levels of androgens (hormones) common in teenagers and people in their 20s. Androgens stimulate the oil glands in the skin. Bacteria on the skin feeds off this excess oil, blocking the pores and resulting in acne.
The best way to treat this is with a course of oral antibiotics such as Oxytetracycline to kill acne-causing bacteria. In addition use a topical retinoid cream called Differin (adapalene) which is very good at clearing up the redness and soreness. Use a bland, soap-free cleanser to minimise irritation. I recommend Effaclar or Physiological Cleansing Gel by La Roche-Posay.
Find a more sympathetic doctor. If untreated, acne can cause physical and psychological scars. It should be treated quickly and robustly and not refered to as "just acne".
Best Wishes, Eloise.