Regenerate is a Spell built explicitly for this purpose and has no costly material components. It is known by every Druid or Cleric capable of casting 7th level spells. A proper Religion or Nature check to know this in the game world and you now have reason to quest to find one.
Your character should have faith in a world where the priest of gods hand out miraculous proof of their existence on the daily basis. You should therefore start climbing the ecclesiastical hierarchy of your religion, being pious, humble and generous with your tithing, and be ready to accept a Geas to perform a quest for the Cleric as the price for what basically cost the Cleric a 5th and 7th level spell slot for otherwise free adventurer labor.
If that's denied because you're being a proactive player in a railroad universe where the DM inflict conditions outside the rules and then deny the rules that allow them being addressed, your alternative which is better than Magic Initiate is Find Familiar gained from the Ritual Caster Feat as Find Familiar is a Ritual, and as an added bonus you gain the ability to cast Rituals. Or have a discussion with the DM or find a different DM if you don't feel up to an uncomfortable discussion.