Well, I had an accident repositioning the bass woofer of my Spirit absolute 2 monitor after checking the connection (keeps cutting out) which was loose. However, I created a new problem as the magnet pulled the woofer so strong that I dented the centre black thin plastic dome in the cone, which was made worse when I tried to pull out the dent, splitting it further. Now the dome has it's shape back but with a few splits and cracks. To my ears it doesn't affect the sound too much except a bit of distortion at certain low frequencies but it looks pretty bad.

Is there something, a rubber solution perhaps I can paint on this to seal it up ?

The 'dome' is really just a cover to keep dust and stuff out of the voice coil gap underneath, so a bit of cosmetic damage is not likely to affect the sound of the woofer very much. You could try sealing any cracks with a little PVA glue (white glue).

I've seen it done with superglue and tissue paper.

Thanks, I managed to fix it by painting layers of liquid latex mixed with acrylic black paint which has worked a treat.