Did you say you wrap the hair around candle sticks? If you do, the tension on the roots will cause that roots to be straight. The rest of the hair being longer, since is wrap up around a candle or small rollers as is the case with many people, will hold the curl; causing the hair to appear straighter at the roots, and much curlier on the rest of the hair.

And no, no tablet can make hair grow faster. Hair growth is genetic. We've all been there. She's gonna have to wait this one out 

try putting some gel in her hair when its wet and hairspraying it. comb the hair and then put the candlesticks in. When you take them out do not brush them, just run your fingers through to get the look you want. This may help. My hair does the same thing i have long thick hair and if i brush the curls, they are gone. And the hair being longer in the back would pose a problem, because the hair is heavier there, so it wont hold as much curl as the shorter hair.