Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
Call emergency services now after any known or suspected swallowing of sulfuric acid.
Emergency help is also needed for:
Elsewhere, use the local poison centre or emergency service.
And for anyone, someone who:
Do not wait for burns or pain to appear.
Begin rinsing exposed skin or eyes immediately while help is being arranged.
If fumes are present, leave the area without putting yourself or anyone else at risk.
Contact a poison information service promptly after any exposure, even if symptoms seem mild.
In the United States, Poison Control is available at 1-800-222-1222.
After hospital discharge, seek urgent assessment for worsening chest or abdominal pain, fever, breathing difficulty, repeated vomiting, vomiting blood, black stools, or inability to swallow liquids.
Arrange routine follow-up for gradually increasing swallowing difficulty, food sticking, ongoing cough, weight loss, slow-healing burns, scar tightness, or continuing vision changes.
Every sign above is quoted from the sofidex article on Sulfuric acid poisoning. If you are not sure, err upward — it is always reasonable to be checked.