No need to worry! The red droplets you see in your butterfly habitat after your butterflies emerged is called "Meconium". The presence of meconium is completely natural--it's the leftover part of the caterpillar that was not needed to make the butterfly. Meconium is stored in the intestine of the butterfly, and it is expelled after the butterfly emerges.
To keep your surfaces safe, be sure to place a few paper towels underneath your butterfly habitat to absorb the meconium.