Ooohhh don't do that.
Taking two pills on random days won't help, it will make it worse.
You just need to keep taking the pills as directed, and the spotting will go away. If you've been on it for awhile (more than 3 months) and the spotting is bothering you (and not going away), you can switch to a different pill.
But it's probably just from something weird, like a change in eating patterns or sleep or something. Don't worry about it.
The fact that you are spotting doesn't mean you are less protected, either. In case you were wondering.