Kind suggestion: never with any system or hardware, please don't touch any alpha/beta quality software before you are fully fluent in your restore and recovery procedures, with Mikrotik it means - how netinstall and winbox are working. As with any crisis/recovery plan, you should practice it safely before actual crisis.
You don't tell if you lost connection to WiFi, ethernet or both. If you tried only WiFi then try with ethernet cable. Router should appear in winbox Neighbors tab automatically and if it doesn't have IP-address then click on it's MAC address to enter using this to reset configuration to default or smth. It's a common practice for Mikrotik to disable interfaces that it doesn't know how to configure: restore incompatible backup, wifiwave2 module renames 5ghz interface to wifi1 etc.
Did you just hold the button or were actually able to netinstall your router? Sometimes it's quite tricky to get it done (disable virtualmachine interfaces etc). Most probably you didn't brick your device, it just needs netinstall or access over MAC-address.
For good-quality OpenVPN, install it in some linux-machine (raspberry or better) and just portforward through the stable router.