I am trying to make a potion that will restore Spell Slots. 

This is what I know... 

I want it to work similarly to Both the current Potion of Healing and Sorcerer's Meta Magic. 

My thought is that a player role 2d4+2 and gains a number of points equal to the amount rolled. They can then immediately spend those points to create spell slots the same way a Sorcerer can use Sorcery points to create spell slots. 

I am not terribly worried about how "Powerful" this could be because I planning on adding some terrible side effects and making them rare.  I am struggling to come up with verbiage that does not need to self-explain sorcery points and the like. 

Any ideas? 

try this:

When you drink this potion, if you have any expended spell slots, you roll 2d4+2. You may use this number to recover expended spell slots of up to 5th level. For each spell slot you regain, you must subtract a number from the number rolled depending on the level of spell slot, as shown below.

SPELL SLOT LEVEL	Number
1st	2
2nd	3
3rd	5
4th	6
5th	7

The last time I saw someone ask about a “mana potion” type thing like this I think the conversation settled somewhere around either the Uncommon version restored a single 1st-level slot, the Rare restored spell slots with a combined level up to 2, and the Very Rare restored slots with a combined level up to 3.

Your idea with the 2d4+2 points and potentially being able to restore spell slots with a combined level of 9 with none higher than 5th-level…. That’s pro’ly a Legendary potion right there, at the absolute minimum Very Rare. If you cut it to 1d4+1 it might squee in at Rare because of the somewhat random results… maybe…. Then the 2d4+2 version could conceivably be only (a very solid) Very Rare… maybe… if playtesting indicates it’s not quite Legendary. Either way I would go no higher. Even 3d4+3 would be way, way, waaayy too much.

I'm not really worried about making them OP because I am added some horrific side effects. Including but not limited to, Damage, loss of spell slots, and Indefinite madness. 

Ohh, I would be careful with either a “backfire” like loosing spell slots instead of gaining, or indefinite madnesses. Backfires like that are sometimes enough to make people never use the item. And madnesses, heck some of just the long-term madnesses are more than horrible with even a middling duration. The campaign I’m currently DMing has madnesses as a regular thing and I gotta tell you, some of them can really, really suck really, really bad. Heck, even some of the short-term madnesses are sucktastic if they were to last long enough.