Herbal incense is it ok to smoke?

No: One of the problems is that "herbal incense" can mean anything, and can have anything, everything or nothing in it. Most of it consist of synthetic cannabinoids which are sprayed on inert plant matter. Some of these can be highly dangerous, causing seizures, psychosis, delirium and even kidney failure and death. Other are milder synthetics that do act like marijuana. You are playing with fire.