Edit php for coupons?

Hi,
My site has some malware with links to other pages, and I have deleted most of it. But in the descriptions for each coupon there is still links that needs to be deleted.

When I open Coupons in the Admin panel, the page is transferred to the malware site after about 30 seconds. I have 16 coupons, but I can only see 2 of them, and those two are clean.

I can see in the source of the coupon page that the malware is there.

How can I edit the description for the coupons – name of the php?

Thank you!

Best regards,
Mette

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