Title says it all
Cloudflare will automatically change your DNS records for you to gain access back to InfinityFree hosting.
Make sure that you had verified first your domain to InfinityFree addon domain before you will setup the cloudflare NS on your domain.
I disagree. What do you mean by “gain access back”? Do you want to revert the nameserver change? Or something else?
Make 2 A Records in the dns section of the dashboard, next find the ip of your website. You can find it at ip-api.com Then Make the first ones name blank then it points to your websites ip address. Next make another A Record with the name (www) then it points to the same ip address as the first one.