I used to try that sort of thing... kind of a "Dogs of today's financial news" strategy. It rarely turned out well for me. The outcomes seemed rather random, even as the overall markets were rising.
In Amazon's case, they are only down to where they were on January 25th and the P/E is still 223, so it's not like a 40% off sale.
I'd set a limit order for 2-4% above what I paid to see if I can catch a rebound.