While marijuana is decriminalized in Maryland to some degree, there are still penalties for possession of even small amounts of the substance, and these can increase with subsequent offenses.
Whether you have a medical permit or not, you should understand the penalties that can be assessed for possession of different amounts. Decriminalization is not the same as legalization, the there is no legal recreational use anywhere in the state.
Possession for personal use
Under current Maryland law, if you are found with less than ten grams, you may be fined up to $100 and you could end up with a civil offense on your record. Any amount of marijuana over ten grams is still punishable by incarceration and fines.
Possession with intent to distribute
Depending on the quantity of marijuana and/or how it is packaged can result in one being charged with possession with the intent to distribute. This is a felony and does not require the actual giving or selling marihuana to another. This charge carries a maximum fine of $15,000 and a prison sentence of up to five years.
Actual distribution of any quantity of marijuana is a felony and carries severe consequences including jail time. If you have prior offenses for drug distribution, then the penalties can be significantly enhanced.