The blood tests are to check on triglyceride levels to make sure your liver/kidney function is OK but any such problems are extremely unlikely. Look, if this stuff was that dangerous it wouldn't be on the market. The biggest risk is birth defects (but only while you are taking it) so if you plan on getting preggo you'll have to wait. But it IS a last resort and you should have exhausted all other options beforehand. My advice, go and see a dermatologist.