Just keep checking to see that mold from the towel has not spread to the ooth. From time to time, just check the presence of black spots on the ooth. If there is one or two, so be it, but if this condition continues to grow, you can put s dilute solution made of water and chlorine bleach on the end of a cotton swab and dab it on the spots. This shuold be done carefully and conservatively and this should check any spread of the mold. You will most likely have a nice hatch. You might want to place the ooth, after it has had time to dry out, in a container because that species can give you as many as 200 or more nymphs and when they hatch, they can spread all over a room in no time at all.