Inspect the housing and cap for damage
With the filter cap removed, gently remove the O-ring(s) from the cap and note their location(s). Do not use a tool to remove the O-ring from the threaded portion of the cap. Clean the housing and cap and inspect carefully for any signs of damage. If in doubt, replace it.
On some designs, and on all spin-on filter designs, the sealing O-ring may be left behind on the engine when the filter is removed. Verify the seal has been removed with the filter to avoid accidentally installing the new seal on top of the old. Two rubber seals don’t seal at all, and it will only be a matter of time before the oil pressure in the engine blows all the oil out onto the pavement.