What is this?

This is a picture of an Orange Bud plant that has been under CFL until 2 days ago. It is now under a 400 Watt HPS. It is just starting week 3 of Vegetative, 18/6. Any iinput would be greatly appreciated. I looked at all of the FAQ's and the forum posts on plant problems. I didnt see this and dont want to screw this up. The tips arent yellowing and the leaves that are yellowing are drooping as well. The light is about 3 feet away from the plant. Thanks RIU!!

looks to me like maybe some water was on the leaf or over watering or something. It doesn't look too bad I'd keep an eye on the new growth as long as that looks healthy and the problem doesn't get worse you should be fine.

I would have thought over water, but I learned a lot from my last grow and I am almost starving them compared to last time. Thanks for the reply Pipe, +rep.