Is it possible to have my hair back right after chemo?

Have patience. Many types of chemo disrupt hair growth and cause the hair to fall out. New hair will start to grow when it gets a chance. First you have to be over chemo, and then your bodily metabolism has to restart the hair growth. Generally you will see a start about 4 weeks after chemo is over but it may take up to 6 months to get a decent crop. This may vary a little with chemo type so ask your onc.