K.C.
We had something similar happen when my boy was that age. We bought a few regular, nice smelling (think : lavender or vanilla) room spray & wrapped them in fun wrapping paper (you can also just use plain, white paper & write on it if you want).
We labled each a different name, ie : "Monster Spray", "Scary Noises Spray", etc...After reading a book & turning out the light, we would spray the one he felt was necessary for that night. Then, we would take a DEEP, DEEP smell and say...."AHHHHH, all gone!"
It worked like a charm! Good luck to you, Mama! :-)