You should probably get him a different cone, those made out of plastic are a pain in the ass.
All Four Paws Comfy Cone Pet Collar, Small-Long, Tan https://www.amazon.com/dp/B00AW5GTLM/ref=cm_sw_r_cp_awd_PekBwbTDYKRDT
You can take the cone off as long as u keep an eye on ur pei, having it on day and night could be a nightmare. Take off when ur pei is just chilling on the couch:bed