In this paper, we propose a distributed spectrum decision protocol resilient to primary user emulation attacks (PUEA) in dynamic spectrum access (DSA) networks. PUEA is a type of denial-of-service attack where malicious users can deprive legitimate secondary users (SUs) of spectrum access by mimicking the primary transmitter. Most studies in the literature discuss how each individual SU can develop mechanisms to detect PUEA. We developed the first centralized protocol to help SUs fuse their individual detection results with the help of a centralized controller, to better mitigate PUEA. Here, we develop a distributed spectrum decision protocol in which SUs make individual spectrum decisions and then exchange individual sensing results with their one-hop neighbors to increase resilience to PUEA. We call this protocol, NEAT: NEighbor AssisTed spectrum decision protocol. We also present a detailed analysis of the protocol in terms of the probability of successful PUEA under Byzantine attacks, where the malicious users can lie about their individual sensing results. We show that with negligible communication overhead, the proposed protocol reduces the probability of successful PUEA by up to three orders of magnitude in the presence of Byzantine attacks. To the best of our knowledge, this is the first distributed protocol proposed to mitigate PUEA.