Thanks for sharing your concern.
Also thanks for giving complete history.I would like to explain you that according to the history given,it appears as though your lateral incisor is non vital and has developed periapical abscess
But since you have mentioned in your history that there is no associated pain or swelling and also you can feel the sensation there, then definitely it could be a lesion due gum infection
There is only two possibility here.
Either it is a gum infection causing redness
there due to pocket or the second and most likely reason being the tooth has turned non vital upon receiving the blow directly or indirectly.
Therefore please make a visit to your dentist
and a simple clinical evaluation along with an x ray
will confirm the diagnosis.
meanwhile you can do warm saline rinses.
Hope it helps.