This could be abrasion from unsuitable flooring material, in which case it will heal up now when you’ve put on sudocream and put blankets over the floors. Lionheads are very furry, but their fur is super soft and they are somewhat prone to sore hocks.
There is however a type of mites that like attacking the area around the nails first of all. I’m only mentioning it because sore hocks on the fore paws is unusual, and this seems concentrated to around the nails. With mites your see flaky skin around the nails though. Burrowing mites are found around the world, but how common it is in rabbits varies a lot between countries and regions. It’s not something we often see on these forums, just now I can only recall one case and that was in the Philippines.
Treatment for mites is injections with ivermectin or spot-on Revolution.
(Not that you would, but we always give this warning when there’es mention of parasites on buns: Never use any compound containing fipronil on a rabbit. It’s deadly toxic to rabbits but fine for cats and dogs. It’s very common and sold under many different brand names, for example Frontline.)