My 23 Yr Old Pregnant (18 Wks Along) Daughter Was

My 23 yr old pregnant (18 wks along) daughter was sunburnt on her legs. From hip to ankle on the sides. The area is now purple. I am concerned. This looks like a huge bruise now. We have applied aloe Vera from time of burn and apple vinegar in bath.. The burn is not blistering or painful any longer. Sunscreen of spf 30 spray was applied several times during the exoosure.
What can we do? Will it heal and return to her natural color?
How much damage did this do?