Acne post 20 years suggests that it is associated more so with your lifestyle. Acne post 20 is considered to be a part of a syndrome called Metabolic Syndrome . Unhealthy lifestyle leads to insulin resistance and this leads to androgen imbalances and thus acne.
Next Steps
Visit an allopathic dermatologist near you. You will need prescription medicines and the treatment will go on for some time. PLUS START MODIFYING LIFESTYLE . sleep on time 10:30 pm wake up at 6 am, exercise 45 min everyday (running jogging swimming cycling etc) and visit a dietitian to get a HEALTHY AND BALANCED DIET . This works really well alongside the medical treatment that you will take. Before you choose your dermatologist read this
http://www.skinmatra.com/single-post/2016/07/03/Skin-Troubles-Here-is-WHAT-NOT-TO-DO
Health Tips
All skin issues are not solely cosmetic issues any more. If your skin is unhealthy your body is not functioning properly . Read this article to know what I am talking about :http://www.skinmatra.com/single-post/2016/09/17/Listen-to-your-skin-talk-Here-is-how