It happened to me, too! I was filming a bit part in a movie last summer. The scene took place on an athletic field in the Deep South, temperatures near 100. I didn't apply topic that morning, but some remained from the day before. My hair was pinned up under a hat, so I didn't expect a problem. Besides, Toppik had never run before. I was shooting a scene with two other actors, and between takes one jerk announces aloud, "Ew, there's something green running down the side of your face!" Imagine my horror. I handled it pretty well, though. Brushed it off with the back of my wrist and replied nonchalantly, "Oh, that must be from the stuff the stylist put in my hair." Fortunately, we shot the final take immediately afterwards.
That incident stands out as one of the most humiliating moments of my life. So, I know how you feel. Tonight is the first time I've visited this board, and when I read your post, I registered immediately so I could respond. It's true, some pigment in the Toppik turns green when mixed with sweat, or perhaps the salt in sweat. Don't feel like the Lone Ranger.
I switched to Dermamatch recently and sometimes supplement with Organin. Haven't put Organin to the sweat test, yet. I plan to do so privately in my backyard one day, so I'll let you know how that works out. BTW, Dermamatch is waterproof. It's great because I can swim in public without running to wrap my head in a towel when I step out of the pool.
