What is the ruling on the prayer of one who was afflicted by urine splash and forgot to cleanse it, then performed ablution and prayed? And does the mosque carpet, the Imam's hand, and the things he touched become impure? And is it obligatory to inform those he shook hands with about it?

If your hand is wet, touching a spot with urine spray will, according to many scholars, cause it to become impure. However, some Maliki scholars hold that if urine dries and leaves no trace, its ruling does not transfer to what it touches. It is permissible to adopt this view in cases of hardship. But if your hand is dry, impurity does not transfer to what it shakes hands with or touches among dry objects, and you are not obligated to inform anyone of that. It is advisable to avoid excessive scrupulosity (waswasah) in matters of worship.