How long should I leave my memory foam expansion?

I just bought and received a 3 "double the memory size Soft foam bed mattress topper. My friend has a different memory foam topper, but struggled with it because not allowed to grow sufficiently before use. How long I let it grow to avoid damage to it? Will it grow long? Dimensions Online, said that 76 "x 37" x 3 ", but only about 68" x 30 "x 2.5" at this time. Furthermore, no evidence to get this horrible smell out? Should I use some Frebreeze?

Help Frebreeze. The smell will eventually leave. I think your friend has a faulty Topper. We have one and is shorter and narrower than it is supposed to be. stretch to fit your mattress before to put on his resume. Memory means that if you stay away from it long enough, she comes close to its original size.