Totter tumblr foam mat - how to flatten the edge

[lboogy]

I bought a giant two-sided foam mat which came rolled up on the pattern side I don't like. I've had it a 6 months now and the side that it was rolled up in still has a raised edge which is dangerous for my D.C. who keeps tripping over it.

Anyone got any suggestions as to flatten the edge ? Closest explanation is the one on the attached picture. As you can see this one has just been rolled out but the edge isn't flat against the ground if you see what I mean.

Have you tried rolling it up the other way and storing it like that for a couple of days? I have a yoga mat a bit like that.

Thank you. Yes I've done that left it overnight and still no joy. Might have to leave it like that for days and months on end.

Can you put heavy books or some other heavy objects down on it for a few days to flatten it?

If it is on a hard surface you can also get rug tape which is like velcro to keep it in place, but if it is put on the edges then it would hold them securely down.