Always finish your entire pack of pills, unless you've missed more than 3 pills in a row, then you should throw that pack out and start a new one. Since you've only been on the pills for a month, its completely normal to have spotting. Actually, I've been on pills for 5 years and every once in a great while, I'll have spotting for a day or 2. The spotting usually goes away after the first 2-3 months after you've started pills though. You can help prevent it from that point on by always remembering to take your pill everyday and try to take it at the same time. So even if you start spotting, light or heavy, or even if your period seems to start before it should, keep on taking 1 pill everyday. Your body is just adjusting and the pills will help make your cycle regular after another month or two. Hope I helped! :)