Thin uterus lining

I was told my lining is to thin for a baby to stick most likely,  it's 7mm and it needs to be 8-10. I was giving the trigger shot to try just in case but my question is: if it takes about 2 weeks for im platoon bleeding is there a chance I could thicken 1mm in 2 weeks? The nurse said sometimes the shot can give a burst of hormones but I wasn't sure if it needs to be at 8mm from the start....