what would happen if igneous rock was first exposed to the energy from the and then millions of years later to energy from earth's interior?

If there is too much heat or pressure, the rock will melt and become magma. This will result in the formation of igneous rock, not a metamorphic rock. Consider how granite changes form. Granite is an igneous rock that forms when magma cools relatively slowly underground.

Explanation:

Gradually, the sediment accumulates in layers and over a long period of time hardens into rock. Generally, sedimentary rock is fairly soft and may break apart or crumble easily. You can often see sand, pebbles, or stones in the rock, and it is usually the only type that contains fossils