Let $p$ be an odd prime. $q,r$ are primes such that $p \mid q^r+1$. Prove that either $2r\mid p-1$ or $p \mid q^2-1$ $\def \m {\; \text{mod}\;}$
My Work
$$q^r\equiv -1 \m p\\
q^{2r} \equiv 1 \m p$$
From Fermat's Little theorem we have -
$$q^{p-1} \equiv 1 \m p$$
From this two equation -
$$q^{(2r,p-1)} \equiv 1 \m p$$
As $p$ is odd prime so $p-1$ is even. Then $(2r,p-1) = 2$. So -
$$q^2 \equiv 1 \m p \implies p \mid q^2 -1$$
So, my solution is saying always $p \mid q^2-1$ but I was supposed to prove that only one of them is right. Where I am mistaken?
I'd also like to know different approaches to solve this problem.