Are artificial eyelashes —often made of plastic material, easily applied and removed, and used for a temporary period— not different from the forbidden hair extensions (وصل) which involve permanently or semi-permanently attaching hair to other hair? And is their use considered a change in Allah’s creation, similar to other cosmetic products like lipstick and eyeshadow?

This issue is subject to scholarly interpretation (ijtihad) and there is disagreement regarding it. We lean towards the prohibition of artificial eyelashes. The argument that they are not attached to the hair or do not remain for a long period is incorrect, as the forbidden joining (wasl) does not stipulate the type of material or its duration. If applying artificial eyelashes is considered among the forbidden joining, then it is considered altering Allah's creation, due to the hadith: "May Allah curse the tattoo artists and those who seek to be tattooed... and those who join hair (al-wasilat)... those who alter Allah’s creation, the Mighty and Majestic."