Depends on who you ask. Some say disclosing of an OTC supplement, though banned, is no big deal.
Others say Machida disclosed the OTC supplement as a pretext because he knew he'd test positive for an actual PED, or was using the OTC supplement as a "masking agent."
I assume he's been tested since. The results of that test, when made public, will (potentially) tell us if Machida was actually cheating or whether this is some nanny state bullshit that fucked Hendo, Machida, the UFC, and the card as a whole.
TL;DR - too soon to tell.