may my 4 month old be allergic to amoxicillian?

well, my sister in law has been sick for about a month and was recently diagnosed with phneumonia. so i took my 4 month old daughter to her pediatricians, they said it was a cold virus and gave her amoxicillian. she has been taking it for about three days, and since she has had a really runny stool. i'll change her diaper and it looks like it's dark green dyed. and today it was and orange-ish color. and down below, her whole diaper area, she has little pimple like looking bumps. there's probably only about 10, but she's also a little red. could this be a reaction to the amoxicillian? or is she just getting irritated because of the runny stool because she has the cold virus?

ALSO, she has a white bump on the side of her gum and it's red on the top. is this a tooth and could this be causing the thing they say is a cold virus?

[Dr Rajput]

Hi, welcome to the forum, adverse cutaneous reactions to drugs are common encountered now a days esp. if the person has an allergic past history. Amoxicillin in one of such drugs. But the symptoms you have mentioned may not be allergic manifestation of amoxicillin.

Presence of green stools suggests excretion of bile unchanged in the stools. This can happen due to faster transit of food through the bowel hence, stool remain green. It can happen in conditions like diarrhea, gastroenteritis esp. with pseudomonas spp., malabsorption syndrome etc.

The diaper rash and pimples can be due to bacterial or fungal infection. She needs to undergo serological tests to rule out organisms. If not responding to amoxicillin then other class of antibiotics can be added in combination or replaced. I suggest you to discuss this with your pediatrician. Take care and regards.