I agree with the views expressed by the other doctors.
Oral steroids have anti-inflammatory effects and can help your cystic acne and rash. However, long term use can cause a lot of other side effects and it is not recommended as the treatment for cystic acne. In fact, with continued use, you may notice even more acne lesions appearing as long term steroid use can aggravate acne. There are many other good treatments available for cystic acne.
You should also get your other skin rash examined to determine the cause. While it responds to steroids, it again is not a recommended long term. We should not blindly treat the skin condition with oral steroids without knowing the exact cause.
So I do advise you to see your dermatologist/doctor to treat your cystic acne and skin rashes.
