Spotty Blue Dream.

Well you should be 24-28" away with a true 300w led usually. If you fall out of that range you may be burning it. Especially considering the 24h schedule. Perhaps even more likely is overwatering. The pot looks pretty small which makes this a real concern. Other possibility would be nute burn. She doesn't need to much in the way of nutrients right now. An EC of 0.6-1.0 would be sufficient I guess. If you're feeding based on the nutrient bottle recommendation, this burn is likely, especially if the soil has time release nutrients already. This should help. As with any issue, always start with a pH check.