Then you're pretty fucked, bro.

Sorry...
The best I can think of is use some small container-like device, like a pencil's eraser cap, and eyeball from the full mass a single dose, preferably less, to test. Then you can use this amount and estimate dose repeatedly, but very inaccurately and dangerously. Also, you've got to make sure the powder is quite pure throughout, and not distributed unevenly.
I doubt, unfortunately, that a lone wizard of these arts will appear and offer you a way to accurately measure mass without a scale or a solvent or another means of assessing total volume. Good luck.
EDIT:
You MIGHT try dissolving it in lightly heated cooking oil for a long time. This would not be suitable for IV use, but you could still measure dose through solvent volume and total drug mass. It would work for anything other than injection, I think. I imagine it's not as fast as ethanol, and might take a longer period with some coaxing through agitation and heat to speed it up.
You could also, though more risky, simply put the powder into a graduated cylinder of some kind and measure out thirty equally tightly packed in doses, very carefully. It'd need to be pretty small, though bigger than a 1cc, definitely. You could actually even just try a large syringe. Pack the powder in tightly, and find out how much, for instance, 5-10 units is, then repeatedly measure out that volume of packed drug until you find total maximum doses and then just do the math to find out how much is in each bit.