weird spots on leaf

No, its not bad to have tinfoil or any other reflective surface on the walls. just vent all the warm air out. Its not enough just to put a fan in if the system is closed, there needs to be fresh cool air all the time. get a blower fan and pump the air outside if you can, then cut a hole for intake in the door or wall and put a vent filter over it to keep bugs out. you can spray at the end of the light period, but be wary of getting the flowers wet when they start getting dense. youll get some yield off these plants but youd get a lot more if they were bigger (bushier) when you started flowering. it looks like they were veged under an incandescent bulb. PS- hang your thermometer at the same level as your growth tips and right in the middle under your light to get a better idea of the direct sunlight that your plants are experiencing.. 75- 80F for day, and 10- 15 degrees cooler at night. 40- 50 percent humidity for flowering. you can get a humidity gauge at the pet store for 5 bux. good luck!

PS- heres a good diagnosis page for the future -
Grow Marijuana FAQ, Cannabis cultivation - marijuana growing tips & photos

A million thanks to all you guys out there with valuable information. My resources are very limited...I am using the dull side of the tinfoil. My plants are small because when I started the veg cycle I didn't have proper lights and it took me a month after the veg cycle started to find the proper CFL cool white light bulbs. I veged them under CFL 23w(6 bulbs) for 30 days. Now i finally got my hands on a HPS 250w with great difficulty so started the flowering.

I will move the thermometer as you have suggested aardvark445.

thanks a bunch thanuttiscotsman......

Sorry but I have to agree with Scotsman....tinfoil is indeed bad for your plants....hot spots from your lighting off the foil can burn plants and reflection from foil is poor and uneven at best . You're better off using nothing than using tinfoil.