Resin doesn't just go cloudy after it has been fully mixed. Something in the environment has made this change occur. It could be:
1. Something in your mold has caused this. A detergent or left-over particles from your last pour may have changed it.
2. If you just added your resin over dried flowers and the flowers still had moisture in them this is a BIG reason resin can go cloudy after. Can you save the flowers? We're sorry to say, but from experiences we've had no you cannot. If you try to remove them the flowers will fold in. If you try to add resin back on top of them that will also ruin them.