Extreme Break-Out of Acne (possibly the Lamictal?)

I'm a 57 year old woman who was recently diagnosed as being bipolar.  I was put on Lamictal starting with the graduated starter packet.  I did fine with the exception of a few small and painful sores in my mouth (cleared up after about 3 weeks).  With time I'm now up to 300 mg with the Effexor being reduced…I continue to feel better and better.

Shortly after the med, I broke out in acne; my skin was in great shape prior to this.  This acne is not only new to me, but very extreme.  The majority of my upper arms and back are literally covered and my chest and stomach have quite a few.  Some are all red bumps while others have a tiny white spot in the center of the red mark; none of these come out.  I also had some hard large ones on my face and neck which would not come out.  

I made the mistake of going back on Estratest vs Estradiol at the same time.  This makes a direct correlation between meds and side effects difficult for me.  Recently I went back on Estradiol to see if that helped the acne (too recent to tell).

Since I feel so good and they are not painful or do they itch, my understanding is that I am not allergic to the Lamictal.

This is bad.... any and all input will be greatly appreciated.

Thank you.