How Can Acne On The Arms Be Treated?

Hi Doc I have been taking thyronorm 25 mg since 2 and half years. I started when that level was 6. Then last year when i rechecked it I reached thyroid level upto 2.3 then my doc told me to continue. Now i m having problems in my periods and I m not pregnant. Since 2 months i m getting very less periods, just spotty. what should i do? And i hv never faced problem of acne but for couple of months i m having acne on my arms and its not going. When i popped it out its very hard to get rid of the spots. Thanks