How To Identify If Child Has Swollen Vitamin B12 Tablet Additionally?

i am not if my three year old swallowed vitimin b12 additionally she could taken green tea loss weght pills, this happened an hr agom my 6 years old states that she did not see her swallow anything, and she told me it took me almost not time to find her playing with these pills. I am not to concern abt the diet pills coz the HUGE, i am sure i would listen to her trying to cough, but still kids at this age can swallow even batteries without making a sound, should i take her to the ER? or what symptoms should I wait to see on her if she happen to swallow something? please help I am very nervous, although i cannot be sure she had swallowed something...