Meh. Factory reset it. Set it all up again. Use the same SSID and password so your WiFi devices all reconnect. That's not a big deal, just more work.
Alternatively, you can use a program like Angry IP scanner to scan for devices on your network.
Discussion
Okay. Did all this. 👍
It definitely didn't boot. Now what do I do?
Figure out why it didn't boot? 😜
Reflash the sd card. Still no boot? Plug an HDMI cable into it and hook it up to a monitor or TV and see what it says.