Hi
sec.354 IPC is :
"Assault or criminal force to woman with intent to outrage her modesty.—
Whoever assaults or uses criminal force to any woman, intending to outrage or knowing it to be likely that he will thereby outrage her modesty, shall be punished with imprisonment of either description for a term which may extend to two years, or with fine, or with both".
if you touch the hand of a woman is not an offence primarily, but touch inappropriately with an intention to outrage modesty is an offence.
The intention can be assessed by the woman who interprets it. Is she can make out a case by proving the touch was inappropriate with sexually motivated intention and was an after effect of other actions as well depending on the circumstances and facts of the complaint.
the narration of your facts would have been helpful to give more of an accurate response here.
There is no time limit to file FIR, but for the effective investigation it is better to file as early as possible.
Supreme Court has given a guideline in " Lalita Kumari vs Govt.Of U.P.& Ors"- on 12 November, 2013
to the police to take the FIR within 7 to 15 days of the intimation of an offence and the category of the offences and circumstances are also specified where primarily enquiry is needed.
within