She stiffens at the sound, but only for a moment. After the initial reaction, it seems that she figures out who is here, and relaxes as a result, though she doesn't turn her face to look at him. Whatever the reason, she is not very interested in concealing what she is doing at the moment.

She quietly wipes her face, neither retracting the sentiment nor loudly advertising it. If Joker wishes to speak, he can, but she is evidently not very interested in beginning.