Chances are you might still be able to recover your data. Install testdisk and do a raw scan on the drive/partition. You should be able to see your data and recover. If the data is less than 1GB, you could try minitools power data recovery live CD. I have recovered several GB of pictures even after formatting and installing a linux on a partition.
You could try this also. Runtime Data Recovery or Active LiveCD
If you are working on a real production machine, my suggestion would be to not to have a rolling release distro like Manjaro or Arch.
Even if you have, your mission critical data should be on a separate partition, not in the root partition where the OS is installed.
If the volume of data is not high, use some kind of online storage like Dropbox or Google Drive.
If you see a blank screen while booting, you could choose the second entry from the boot menu "Advanced Options ..." and see if it works. You can ask for help in the forums using a tablet or mobile phone with internet.
Finally, re-installing the OS should be the very last option to try (if you are not a distro hopper..)