it is possible that re fitting your old followers finishedoff your cam mate as they will have worn along with your original camshaft however i have heard many many horror stories with piper and kent cams the material they make them out of is poor to say the least shame you found out the hard way. i would reccomend newman cams for a replacement as they are made out of chilled iron and are extremely hard wearing and dont require the hardening process of revving for 20 mins like the piper and kents do as they are hard as nails already. also prior to fitting i would get the head checked by a proper head engineer as if one of the cast in cam journals is scored the head will be scrap, also check the oil feeds in the head to make sure they are clear as they clog easily
all the best mate