It is very common for skin to break out during pregnancy due to the climbing levels of estrogen and progesterone in your body.
I would NOT advise you to take any herbs to help balance or detox your body during your pregnancy nor during lactation to alleviate this symptom. It sounds like you could benefit greatly by a liver detox AFTER your pregnancy and lactation.
The liver plays an intimate role in the metabolism, detoxification and excretion of hormones. When it is in need of a "tune-up", symptoms like acne during pregnancy can occur. Make sure you're not eating sugar or processed foods as these aggravate the problem. Often, hormones (even natural ones) contained in milk, exacerbate a liver that is struggling to deal with hormones efficiently.
I'm not popular with this belief (and it is based on my 30 years of medical experience), but dairy products for 90% of people whom I see, is a disease producing substance. And in some people, the casein and lactalbumin found in milk interferes with normal calcium absorption.
Make sure your bowels are moving daily so toxins do not accumulate and excrete through the skin. Drink 3 L of water daily. Take Flaxoil or Flaxmeal if necessary. Eat lots of fruits and vegetables. At least 10 servings daily.
White spots on nails. Could be any number of things. Zinc deficiency and calcium deficiency are among the possibilities. I would strongly recommend that you see a naturopathic doctor to determine if there is a mineral imbalance. Your baby will do better when you are nutritionally balanced.
I use a Sulkowich test for determining Calcium, among other tests.