Given an elliptic curve $E$ defined over $\mathbb{Z}$, and a prime $p$, I know that Hasse's theorem gives, *when $p$ is a good prime*, a relation between the number of solutions over $\mathbb{F}_{p^n}$ and the number of solutions over
$\mathbb{F}_p$ (for this, the coefficients of the equation are reduced mod $p$).

Is there such a relation also at the bad primes?