Yes, for drugs possession it is the final conviction that counts. So you’re in the clear…..unless
the incident had some bearing on you DL history. Once a car or boat where You are the operator is involved, it all changes. Every arrest for DUI—drugs or alcohol, regardless of the final disposition has to be reported. AOPA has an explanation, since there are different reporting requirements before & after 1990.
if there is ever any doubt in your mind, join AOPA at the pilot protection level & get free factual advise from AOPA affiliated doctors & lawyers on almost any topic.
standard POA list advice: if there is ever any doubt about any medical condition, rx drug, or history, get an ”advisory” appointment with the AME. Never fill in the online form until you are 100% certain you will pass. Instead, print it out & take it with you to the advisory exam. Sometimes, It is just a matter of switching to an FAA approved drug for your condition.
yes, you will pay for two physicals, but but the time & pain involved in being denied a physical & having to go through the SI(special issuance) process is worth it.
Any history of Depression, ADHD, etc. require special handling. Like the military, until recently the FAA would rather have you self-medicate with alcohol (as long as you don’t get caught behind the wheel) than take an antidepressant.
good luck.