Homebrewed Spell: Runes of Radiance

[JankShenanigans]

Hey everyone!

I've been working with my DM to create a spell for the fire genasi cleric I'm playing in his campaign. We'd love to have some feedback on what y'all think in terms of power and balancing.

Runes of Radiance
7th-level evocation

Casting Time: 1 action
Range: Self
Components: V, S, M (a set of rune stones worth at least 25gp)
Duration: Instantaneous

Runes appear in the air around you and begin to spin, creating a blindingly white fire storm. The storm is a cylinder with a 30-foot radius and reaches 20 feet into the air. Each enemy creature in the area must make a Dexterity saving throw. It takes 6d8 radiant damage on a failed save, or half as much damage on a successful one. Friendly creatures in the area of the spell regain hit points equal to 4d4 + your spellcasting ability modifier.
At Higher Levels. When you cast this spell using a spell slot of 8th level or higher, the damage increases by 1d8 for each slot level above 7th.

[Princess]

Hey everyone!

I've been working with my DM to create a spell for the fire genasi cleric I'm playing in his campaign. We'd love to have some feedback on what y'all think in terms of power and balancing.

Runes of Radiance
7th-level evocation

Casting Time: 1 action
Range: Self
Components: V, S, M (a set of rune stones worth at least 25gp)
Duration: Instantaneous

Runes appear in the air around you and begin to spin, creating a blindingly white fire storm. The storm is a cylinder with a 30-foot radius and reaches 20 feet into the air. Each enemy creature in the area must make a Dexterity saving throw. It takes 6d8 radiant damage on a failed save, or half as much damage on a successful one. Friendly creatures in the area of the spell regain hit points equal to 4d4 + your spellcasting ability modifier.
At Higher Levels. When you cast this spell using a spell slot of 8th level or higher, the damage increases by 1d8 for each slot level above 7th.

This looks pretty well designed but it's probably better than most AoE or healing spells that just do one or the other at level 5, which makes me suspect either 7th level is too low, or the dice should be shifted downward a bit. But it's pretty darn close to right and thematically excellent, so I'd probably playtest it, as is, and pay attention for a few sessions to see if it feels too good or just right. I really like the idea behind this and the visual is great.