Enhancements Permission blah blah?

I'm 13 and I'm really really flat chested and I have stayed the same size for a LONG time so I searched in intanet and found these Enhancement Creams for 13-17 year olds and I want to get it but I can't coz my mum will av to buy it n i dont want her to find out coz she wnt let me. What can I do?