Exceptional point (EP) degeneracies are non-Hermitian spectral singularities where multiple eigenvalues and their corresponding eigenvectors coalesce. This collapse of the eigenbasis has profound implications for the system’s response and enables a range of striking phenomena, such as unidirectional invisibility, hypersensitive sensing, loss-induced transparency, and EP lasers. A key ingredient behind many of these effects is the enhancement of wave–matter interactions near an EP. EPs typically emerge from symmetries in the non-Hermitian Hamiltonian, most notably parity-time (PT) symmetry. When this symmetry is broken, the system shifts away from the EP regime. In this work, we use analytical and numerical methods to show that phonons can dynamically restore an effective PT symmetry, leading to the formation of an EP in nonlinear non-Hermitian polariton systems. This mechanism unveils a new route for engineering and controlling exceptional point physics through vibrational modes.