Any one help me

Pr

My follicle test on my cycle on 12 after taking letrozole...according to scan I was ovulate next 2 day(14 DAY)......I regular check ovulation on prediction kit ....but no LH surge.....today I text to dr....and dr told today use a ovidrel injection ON CYCLE day 17....I don't no its work or not........any one know about this......thanks...