Assuming you have correctly followed the 5 step guide to using R.I.P. Fleas Extra and have also treated your pet(s) with an appropriate product, if you are still seeing fleas and/or getting bitten this is more than likely due to the pupal window effect. No environmental flea spray is effective against pupae, so new adult fleas will continue to emerge from the pupae into the environment after spraying. Once the adult fleas emerge, they will be killed by both R.I.P. Fleas Extra and the product you have applied to your pet. Depending on the severity of the infestation, it can take several months to fully resolve.