Continually Using Drugs

If I continue to use drugs (cannabis, psychadelics, etc) will my recovery process be longer or is it a set clock of recovery that just resets whenever I use. My symptoms get a lot better a few weeks after I stop use, and then I keep just starting again and setting myself back because I feel like I'm doing better. Also, will there ever be a point after my HPPD goes away that I will be able to use again without it redevelopment?

Sorry if these questions seem obvious I'm genuinely curious!