If you do not mention you used abortion pills and you did not use Misoprostol vaginally there is no way they can know or prove you induced an abortion with pills. Mifepristone and Misoprostol cannot be detected in your blood or your urine, so even if they run tests they cannot confirm that you used these pills.
If you inserted Misoprostol pills in your vagina they may be able to see remains of the pills. If you used these pills vaginally and you need medical care try to carefully remove any remain of the pills from your vagina before going to a health center.
Although medical staff cannot prove you used abortion pills unless you used Misoprostol vaginally, they will know you were pregnant and probably will think you are having a miscarriage (natural abortion). The complications from a miscarriage and from an abortion are exactly the same so even if they do not know you used abortion pills they can treat you properly. You do not need to disclose that you used abortion pills if you do not want to.