What does the narrator mean when she says," these days are ill-defined in my memory, running together and combining like a fresh watercolor painting left out in the rain"? what type of literary device is author using

Simile

The narrator is comparing the way her memories run together and combine then disappear to a watercolor painting left out in the rain. When a watercolor painting is left out in the rain, the pain will wash off combining as it drips down and then disappearing altogether off of the canvas. The comparison uses the word "like" which makes it a simile instead of a metaphor. This is also a great example of imagery because the reader can picture the memories melting together and sliding away.