I am a male first of all and I lost a bad bet to go tanning for 3 straight months... in a bikini. I am no left with very embarrassing tanlines and designs. How long will they last? Can they be permanent? Anything I can do? They are dark and prominent

6 months out of the sun should fade them enough. Or tan without them. They will level out pretty quickly. Apply a stronger sunblock to already tanned areas to aid in the leveling.

And don't make stupid bets. :)

I lived on the beach in Florida and practically lived in a bikini for two of my teenage years. I had an incredibly DARK, natural tan and incredibly white tan lines. Almost three years after moving to Indiana I realized I still had my tan lines from the bikini days. I'm sure yours will fade much faster. Stay away from tanning beds though- my arms and legs have developed ugly spots from sun damage. Now I'm embarrassed to even wear shorts and short sleeves! It's just not worth it.