The information provided by Eddie is not correct in one important respect.
I agree that from your description that this does seem more serious but if the offence is Common Assault it cannot be referred to the Crown Court for sentencing. Common Assault (unless racially or religiously aggravated) is a “summary” offence and can only be dealt with at the Magistrates’ court.
As Eddie correctly points out the maximum sentence is six months custody. Magistrates sentencing guidelines suggest that custody should be considered when two or more aggravating features exist. The fact that this was committed in a domestic setting certainly aggravates the offence. This together with the nature and extent of your injuries certainly seems enough to pass the custody threshold.
I assume your ex is remanded in custody awaiting sentence. The magistrates will have given an indication of the type of sentence they are considering and from your description of events it seems that custody is a strong possibility. You should bear in mind that although the maximum is six months, your ex will receive the maximum discount of one third for his early guilty plea (making the maximum four months) and if he is sent to prison he will serve just half of his sentence inside (making the maximum two months). Any time spent in custody on remand will count towards the time served. You should also bear in mind that if he has not served time for offences of a similar nature before, there is a possibility that the sentence will be suspended.
Perhaps more important than the sentence from your point of view is that you should ensure that
the prosecutor asks the Bench to impose a restraining order preventing further contact.
I’m afraid I’ve not heard of “j.c. bail” so cannot help unless you tell me what you mean.