All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
Supplicating Allah by His name, The Beautiful (Al-Jameel), and His love for beauty is permissible. There is no harm in making supplication for attainable beauty. This includes praying for increased physical beauty that could be achieved through lawful means, or for inner beauty of the heart and soul, which manifests outwardly as radiance and prettiness (on one’s face), and other similar possible and permissible things.
Ibn Taymiyyah states in “Al-Istiqamah”: “Goodness and beauty derived from righteous deeds within the heart manifest on the face, just as ugliness and unloveliness stemming from bad deeds within the heart also manifest on the face.”
However, what is prohibited is to make supplication for beauty with the intention of altering one’s creation in a way which is ordinarily impossible or with the intention of altering it in an unlawful way. An example of transgressive supplication is to ask for something ordinarily impossible or for something which is forbidden by Islamic Shariah.
In “Bada'i' al-Fawai'd”, Ibn al-Qayyim explains: “Transgression in making supplication is to ask for anything that contradicts Allah’s wisdom, negates His law and command, or opposes His established knowledge. This is transgression, and Allah does not love it nor the one who asks for it.”
Allah knows best.