Interesting drawing. I am no expert but The lotus starts its life in the mud, grows until it breaks the surface of the water, where it is changed from the plant to the flower. In Buddhism like many Asian religions the Lotus is a symbol of rebirth as a better person. The frog is an amphibian that moves from living in the water to living in land. The frog is seen in some Asian spiritual schools as a symbol of transition or transformation from one stage of life to the next.
I believe the combination of the frog and the lotus symbolizes the growth and transformation or transition of a person from a lowly creature living in the mud to a much better person now living on the top of the water and perhaps land. The mud and land being metaphors for living a good or bad life or a dirty or pure existence. That would be my interpretation of this frog on the lotus juxtaposition.