I'd advise against it.
The government hasn't slashed the taxes yet. The custom officials will rape your wallet! And even though it's a used phone, they're going to charge taxes according to its original value, which is batshit crazy! And let's not forget PTA which has become a total pain in the bottom in recent months and been blocking phones like crazy.
Best to find a local, PTA approved specimen on OLX etc. If you're from Lahore then you may want to pay Hafeez Center a visit. Plenty of shops there which sell imported (smuggled) iPhones.
Hope it helps.