Do fortify armor potions do anything?If I drink a fortify light armor potion,say it's 30%,does my armor rating actually go up?Or is it only perks that raise your armor rating.
I don't want to spend very many perks on light armor for this character and was just thinking about making potions instead.

You could always drink one and see for yourself. Only downside that I can see is that the potions last for such a short time, but yes, according to the wiki your armor skill will go up

If (just after taking said potion) you pause and go into the "magic" menu then down to "active effects" the potion, it's effect and how long you have left will be there.

Fortify armor potions add points (10-25, depending on the potion's strength) to your light armor skill (potions of the skirmisher) or your heavy armor skill (potions of the knight).

Yeah I tried a fortify light armor potion that raised my light armor by 10 points,but it only raised my armor rating by 1 point.
That seems like a worthless potion to me.

Check your Constellations - if your Light Armor skill is green then it's number has been magically/artificially enhanced. Numerical ratings in this game seem to have a minimal effect - the numbers are mostly just useful for unlocking the perks so you can select them.

I just drank a potion with fortify Heavy Armor 10 points, and my Armor Rating went up by 5 points. Fortify 20 points gave me +12. My base rating was 71. The higher your skill, the more of a boost you will get.

I second this, but my skill isn't as high so I got +5 and +10.