do you have steri strips? if so,wash hands hold incision togeather and apply a few of the strips,You will also need to keep you dog from licking the incision,do you have plastic collar that keeps them from getting to the incision? They also sell cream that tastes bad u can apply that deters them from licking. Good luck:)
If the wound was bad enough to need stitches and you say that it is gaping open, even though it isn't bleeding you need to take him back to the vet (or to an emergency vet since it's the weekend) and have the stitches put back in. The reason you don't want to wait until Monday is that enough healing will take place between now and then that you will not be able to just resuture it on Monday without debriding the wound (re-cutting the edges so they are newly cut), so you need to get him back in ASAP to have it resutured. If you leave it open and just let it heal on its own, chances are it will, but it will leave a large scar because scar tissue will need to form to fill in the gap between the edges of the cut.
As pruiz34 stated, if you have a butterfly bandage you MAY be able to pull the edges of the wound close enough together to make it work, but ideally you should let a vet take a look and actually put the sutures back in.
Please let us know how he's doing.
Thank you guys for your response. I couldn't take her until this morning ,but thank god she is doing great . The vet re-stitched the wound and they put little boots on her back legs so she won't scratch the stitches off again , she looks so funny . Thank u guys again ..