Replying to Stretching a jiberish hoodie

I tried streching out the bottom (elastic?) band out on my jiberish hoodie cuz it creeps up and eventually ends up around my waist, when i walk and ski, buuuut when i did this the band didnt stretch out that much and the bottom of the main fabric (under the pockets) really steched out wide. now i look like a fuckin cupcake when i put it on. i feel like an idiot.. does anyone know how to stretch out the bottom elastic part? or fix what ive done to mine???