[Tacopuck]

Hard to say without knowing exactly what you do currently, how much you are compensated currently and how much extra work will be coming your way.

That said, given your relatively junior status in the field you're in (assuming there wasn't any relevant experience prior to the 3 years) I'd take this as an opportunity to grow your skill base and show management that you can handle the higher level work and then use that as leverage for additional compensation / promotions later on after your boss returns.

Worst case your current company doesn't care (ie no compensation / promotions), but you've at least developed new skill set that you can use at other firms in the industry.

Just my personal opinion.