Hi @cactus_1549,
Does it look like [https://www.walmart.com/ip/5H40J79872-Lenovo-Cpu-Heatsink-IDEAPAD-MIIX-300-10IBY-TABLET/346718374|this]?
If so then yes it has to be replaced because it is part of the heatsink for the CPU.
Search online for ''5H40J79872'' to find suppliers that suit you best.
Here's the [https://download.lenovo.com/consumer/mobiles_pub/ideapad_miix_300-10iby_hmm_201507.pdf|hardware maintenance manual] for the tablet that may be of further help if necessary.