Hi Sally
I’m Eliisa from BCNA’s Policy team and I’ve done some investigating on skin issues when taking Tamoxifen.
A listed side effect of Tamoxifen's is ‘skin changes’ but there is nothing specific about pimples, acne or spots. Patients are advised to seek medical attention if they are experiencing a rash or blistering of the skin. Another side effect could be dryness which is causing acne like irritation.
I’ve also been on some of the other breast cancer forums around the world and you aren’t alone in experiencing this problem with your skin. Many other women have commented on experiencing jaw and hairline acne since taking Tamoxifen. Some of these women’s oncologists have advised it’s due to hormonal changes from taking Tamoxifen. Unfortunately, there haven’t been any clear solutions except over the counter acne regimens.
If you are concerned about it, we would recommend you speak with your oncologist.
Hope this helps
Eliisa