Lash perm hasn’t taken to lashes

[Lrp]

I’ve been using nouveau sachets and left step 2 the perm on my clients lashes for 8 minutes. The lashes didn’t take to a xs shield and her lashes are left straight . Can I perm them again the next day or leave it a few days? Or what can I do to try and perm the lashes again? I live in dubai so wondering if the sachets have ‘gone off’ I only purchased them 2 months ago