Good news / not so bad news, preliminary.
Good news here is the part:
Diagram of OEM Lighting, Outside Mirror. Contains Lamp. Puddle. Led. Left for Lighting, Outside Mirror. Fits 1500.
www.moparpartsoverstock.com
I have a mirror that I purchased off of ebay to practice removing the mirror glass prior to attempting replacement of my mirror covers. The mirror glass would need to be removed first. There is a posting on mirror cover replacements.
I miraculously got it back together, not without breaking half the tabs and what not. Took me 2 hours to figure the damn thing out... the motor housing easily snaps out of the mirror housing. There's a T10 Torx screw in the middle that also holds the motor housing to the mirror housing, and also...
5thgenrams.com
I believe the key to removing the mirror glass is temperature and patience. With the glass mirror removed there are 2 screws that I can access for the turn signal lens however something else is stopping me for complete removal at this time.
So it looks like you can replace the turn signal but you need to remove the mirror glass which can be tricky but readily doable. If you order the part I believe you will see what holds the mirror turn signal on other than the two screws.
Sorry about your mishap, hope this gives some relief.