twisting curling burning

This is my first time growing, so im just kinda goin with the flow. but the tips of some leaves are turning a brown/yellowish and seem to be dying. also, one of my leaves had curled completely in on itself. its about 9 weeks old, on a 12 hour light cycle. i have no idea what to do. please help...

What Strain is it? Jamaican Is it Indica, Sativa or Hybrid? What percentages? Don't know How Many Plants? 275 Is it in Vegetative or Flowering Stage? Flowering If in Vegetative Stage... How Long? If in Flowering Stage... How Long? 4.5 weeks out of 8 Indoor or Outdoor? Indoor Soil or...