All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
When the blood of a woman stops after her usual monthly period and she becomes pure, either by seeing a white discharge or becoming dry (and this is a matter which a woman knows from her regular menses) then she is pure and she is obliged to perform Ghusl (ritual bathing); in this case her prayer is valid and her fasting is valid. It is permissible for her husband to have sexual intercourse with her, and the red or brown spots of blood which she has after that have no effect, provided that these blood discharges do not come out after the minimum period of purity of fifteen days. If the discharges come after the minimum period of purity then they are menses, in which case, fasting, the prayer and sexual intercourse are forbidden. Your case should be applied according to the above details.
For more benefit, please refer to Fataawa 91497, 91486, 91444 and 84477.
Allaah Knows best.