is not possible for her to drink the twilight alicorn medicine because twilight a drink it the all potion and she turn to a baby for it, only Twilight a get other of it but with no side effect but the potion is for alicorn only, so is possible to a none alicorn drink it get the side effect!
Speak English.
Either that or it’s because she isn’t an Alicorn.
Guess Glimmy didn’t drink as much.