Key blinding produces pseudonymous digital identities by rerandomizing public keys of a digital signature scheme. It provides privacy in decentralized networks. Current key blinding schemes are based on the discrete log assumption. Eaton, Stebila and Stracovsky (LATINCRYPT 2021) proposed the first post-quantum key blinding schemes from lattice assumptions. However, the large public keys and lack of QROM security means they are not ready to replace existing solutions. We present a general framework to build post-quantum signature schemes with key blinding based on the MPC-in-the-Head paradigm. This results in schemes that rely on well-studied symmetric cryptographic primitives and admit short public keys. We prove generic security results in the quantum random oracle model (QROM). We instantiate our framework with the recent AES-based Helium signature scheme (Kales and Zaverucha, 2022) to obtain an efficient post-quantum key blinding scheme with small keys. Both Helium and the aforementioned lattice-based key blinding schemes were only proven secure in the ROM. This makes our results the first QROM proof of Helium and the first fully quantum-safe public key blinding scheme.