Time is not always simply chronological, a span of time, for example "now", includes anything from the past that is still influencing you or not yet resolved, it is not yet "in the past". "Now" also includes your future, worries, hopes, plans, dreams.
Unfinished business is important to attend to. Imagine you are carrying around a large suitcase full of your unfinished business. The suitcase doesn't have wheels, it's pretty difficult to carry, and it's getting in the way of you getting on with your life.
We can never truly get rid of our 'baggage', but we can find easier ways to carry it. Processing it, and thereby reducing it down, may mean it now fits in a small back pack, easy to carry and not getting in your way. Still with you, but not interfering in your day to day life any more.
Think about how the painting exercise made you feel. As well as the actual feelings your pictures brought up, think about how you felt painting the picture, how you felt just as you had finished painting and handed the brush back, and even how you felt walking out of the room without your picture. Was this a useful exercise for you? If it was, how might you be able to use this experience for yourself again? If it wasn't, why not? Were you ready to paint your picture? Were you surprised at what you painted? What else happened for you?
Remember to take care of yourselves during this process. Identify and use strategies that help you cope better with painful feelings. Remember the support of the group, you are all there for each other.