If she felt only "a little bit" of heat, you know her metabolic rate wasn't being raised very much. D sells crystal DNP which is 75% actual DNP by weight. 200mg of crystal DNP contains 150mg of actual DNP. However, D is known to have issues with dosing consistency, so she was probably getting somewhere between 100 and 150mg of actual DNP.
Based on the research by Cutting and Tainter, that would correspond to an increase in metabolic rate of 15 to 22% in someone with average sensitivity to DNP. Your friend might be more tolerant than the average person, which means it would increase her metabolic rate even less. Using the average though, let's assume your friend weighs 145 and has a normal daily energy expenditure of 2175 Cal (15 Cal/lb). At 15 to 22%, that means the DNP would burn between 326 and 479 Cal per day.
As you can see, it's nothing huge. At that low dose of DNP, she'd be expected to lose less than a pound a week. If she ran it for 14 days, you're looking at 2 lbs of fat loss. And if she compensated for what the DNP was burning by eating more calories or being less active, she could have easily cut that in half, to only 1 lb of total fat loss.
To top it off, she doesn't have a scale and doesn't even know what her starting weight was. How many women are capable of discerning when they've lost only 1-2 lbs?
I don't think there's a mystery here at all.