Restore previous version of css/php files

After the theme (Head Blog) had updated I noticed that the css and php files of my site had been restored. All the changes I made are gone and I was wondering if there is a way to get the old ones back.
I just started creating websites and did not now about child themes etc. so I have no backup on my own laptop.

Thank you in advance!

• This topic was modified 7 years, 8 months ago by purposelyplantbased.