Loki was looking at her "Hold still." He places his hand where the wound is and uses his magic to ease the pain and heal it a bit so its no longer bad.
He hardly ever heals anybody unless they are important to him. He had only last used his magic to heal Thor once.
The god knew that his magic would help her feel better. Loki knew his magic couldn't always do everything. He knows fixing certain things is too hard or impossible.