If you hearken back to prom, exam time or even your wedding day, you might find that there’s a common thread tying them together … you probably had a zit — or three.Why? Stress. Recent studies have shown a direct link between stress levels and increases of acne. Scientists now believe that during times of stress, our bodies release elevated levels of two hormones that stimulate the sebaceous glands to produce excess oil. And, of course, that excess oil leads to clogged pores, blackheads and acne. Additionally, stress slows down the healing process — it can decrease the wound healing capacity of the immune system by up to 40 percent so that your breakouts will last longer than usual.