Half and half. Chelation moves some heavy metals around, and some out. It makes sense that a bit of it has ended up in your skin.
The infections/hives are likely related to the bacteria that like to use heavy metals as their foodsource. They are in the same family as extremophiles which create veins of gold in deep soil and rock- they feed off minerals and put the excess in their cell walls, which in part acts as a defense against other microorganisims (such as white blood cells) which would wipe them out.
The bacteria which feed on those sorts of heavy metals generate ROS (Reactive Oxygen Species) particles, and those in turn show up as inflammation.
Reccommended treatment would be a pulling agent (hydrated Bentonite clay, magnesium sulfate soaks, coconut oil salve) on the skin at the infection site(s) and a nutrient-dense diet.
Keeping the sites moist with coconut oil between bentonite/magnesium sulfate daily treatments would be ideal. Coconut oil helps destroy those kind of infections.
Continuing DMSA can continue the process of wiping out those infections, but there needs to always be a rest period for rebuilding your glutathione stores and alkiline minerals. If you're in a rest phase, please use the above methods.