I often use
http://christiandreamsymbols.com It's kinda basic, but I can usually unravel a dream by going to various Christian Dream websites.
This website says of:
Mask-someone who has a mask or disguise on during a dream is symbolic of deception, 2 Cor. 11:14
Faces-faces are symbolic of humanity. If the face is pale it symbolizes death or anguish, Joel 2:6. A gleaming, smiling face symbol*izes joy and peace. A face without eyes, ears, or mouth is symbolic of being deaf and dumb to the gospel, Ezek. 12:2
There had to be 2 applications of the mask:
2-symbolic of unity and Christian work, Lk.10:1-3
I would also check the color of the mask.
The mask didn't fit right, so maybe someone is trying to deceive you and coming back at you with a second try?
Or is someone trying to look like they are in unity with you and really not?
Just some thoughts...