[That's the first non-hostile sentence he's been offered since he's met the other.]

Let you see me. [It's fine, he's pretty okay with the question.] I can't restore your sight, but I can at least give you an idea of who you're talking to.

[When soldiers in the armies he led lost their sight, they were terrified and angry. He can't imagine what it's like to be blind, but he knows he can help, somewhat.]

If you don't mind, that is. [A thought occurs to him that the elf may not want it, so he offers it as an option. The less tense Lavellan is, the easier it becomes to work with him.]