methimazole and cold temps

i accidently left my cats transdermal methimazole outside today in about 20°F weather for about 3 hours. i didn’t realize it was delivered, let alone left outside as my delivery driver NEVER leaves our packages outside. anyway, the consistently and color of the medicine looks all normal, and is not frozen, just colder to the touch than normal. is it still safe and effective to use for my girl? i am going to call my vet tomorrow too, just wanted to see if it happened to anybody else before.