Need help fast with stem issue!

My Fem WW plant has been growing for about 3 1/2 weeks now. Today when i went to check on i noticed a brown spot on the stem and she was leaning at that spot. Can anyone tell me why this is happening? What should/can i do to save it?

looks like damage from some big crazy insect. insert a small stake and gently tie the plant to it. GL

Thanks Po boy, I tied her to a stake today and i have a mini fan aimed directly at the spot. I read somewhere that it could be stem rot. I really hoping everything works out for the best!

peroxide really helps with hydro and root problems. not sure of the exact link but here are a couple.. oh here it is..http://www.quickgrow.com/gardening_articles/hydrogen_peroxide_horticulture.html

and another http://homeguides.sfgate.com/hydrogen-peroxide-plant-fungus-86713.html

thanks for the info Sativa Indica pits, I picked up some peroxide and treated the water. The roots seem fine, its just that one part on the stem. I read that it can happen from the rockwool being to wet, which I have fan directed at that spot. I treated her with the peroxide at the spot and also treated my nute solution and diluting it with more water.