The general answer is to not make new jerk reactions when a fund touches a low. Mid and small cap funds have given good returns over the last 5 years. Now some of them are averaging out.
Another reason why these funds are correcting is because the new mutual fund re categorisation mandated by SEBI is forcing many funds to prune their holdings and therefore many are selling out small caps. The sell pressure is impacting prices to some extent.
If the fund you have invited in has a good track record vs the market, do HOLD on. It might be a bumpy ride but if your goals are long term,
This also depends on your appetite for risk. Find your risk profile here and based on that go for an asset allocation with help of a SEBI Registered Advisor.