I've had hard inquiries show up on my credit report the next day after applying for a loan or credit card.
The hard inquiry can drop your score by 7 points but the hard inquiry is usually removed from your credit report within 2 months but sometimes sooner.
Once the hard inquiry is removed from your credit report then your credit score should go back up to where it was before.
Avoid applying for too many loans or for too much credit since too many hard inquiries and loan applications can cause your credit score to go down a lot.