One of my parents claimed me as a dependent when I haven’t seen them for years and I already filed my taxes online, can I get penalized for this? If I can what do I do?

[MaryK1]

If you do not qualify as their dependent, they cannot claim you.  If they can properly claim you, you will just have to amend your tax return.  There is no penalty unless you had fraudulent intentions.  If you received a refund and should not have, you will have to pay it back.  See the qualifications below.

https://ttlc.intuit.com/questions/3113432